You've activated my trap card!

This is sort of a vague question actually. What depictions? What does miserable mean? So I'll give you a bit of everything.

Is the Medieval Period a nice period? No. Is it well depicted in media? Not particularly, but what period is? Is it a worse period than now? Most people would say yes, our lives are better.

One of the problems with the depictions of the Medieval Period is the "Dark Ages" trope. While it's true that the fall of Western Rome did cause certain technology, structure and culture to be lost that the native western people of the time did not well preserve. However the extent and importance of this loss has been exaggerated, as has the supposed disappearance of writing and study for some 200-400 years or whatever. Janet Nelson ("The Dark Ages", 2007) points out the abundance of Early Medieval evidence that has previously been neglected. Walahfrid Strabo, one of the earliest people to promote this idea, did it in a history of Charlemagne's reign talking about him bringing the light of God, obvious motive is obvious, but Nelson points out the significant religiosity and importance religious developments of the Dark Ages that were already occurring before Charlemagne. The idea of the Dark Ages has nevertheless influenced understanding of the Medieval. if they were so bad how much better can the Medieval Period before the Renaissance have been? Some people have at previous points even called the entire Medieval Period The Dark Ages. That's poppycock.

So what was the Medieval period like? That's far too complex a question to answer; although /u/sunagainstgold could probably help. But I'll give you a few points.

First, if you think people didn't wash themselves or clean things, you are wrong. The Roman baths didn't immediately go away when Western Rome fell, and the Crusaders brought back the tradition of Turkish baths. There were bathhouses in every major English city during the High Medieval period. I can't imagine everyone using them all the time, especially if you were in the country, but they were there and they were definitely used a good amount. In addition the washing of underclothes was a long running tradition. Using a washbasin of cold water for the face and hands was a thing, as was washing your hair; you might do that in a bathhouse or at home. Soap and perfumes were also things so if you could afford them, and most people could at least afford a small amount of soap for underclothes that helped with smells. At the bathhouses they sometimes put spices in the water source for aromatic steam. And you can always dip in a river or stream. Drains in the floor were a thing in at least some kitchens and other places that would go to their own waste pit. There's no point in history where people just don't clean. Lucy Worsley does a decent cover of this, although some of it is a little simplified (An Intimate History of Your Home, 2011) Can also find the documentary version, History of the Home, on Youtube.

Second thing I would add is that fiction often depicts Medieval times as pretty non-procedural. Look at Game of Thrones, which is particularly heinous because it's set in roughly the equivalent of the Late Medieval, where nobles and the king often just seem to do whatever they want with only certain rules, procedures and non-inherited power structures, none of which limit them very much at all. That's not quite right. While nobles and monarchs did hold a lot of sway, their power rested not only in themselves but in their ability to work with and use the rules, procedures and structures. I'm gonna poach a little from a previous answer of mine: "Even when kings were holding court in the full curia regis style the people who would become judges, law clerks, were still their give formality to the process and witnesses and other evidence was always a thing. A finalis concordia was a sworn agreement in Anglo-Saxon England between disputing parties in a royal court, a formal system of settlement (Doris. M. Stenton, 1969, 2019 edition) . While the power to administer justice at their own will was a thing early on for many kings, and many retained it, even then it was done with something approximating a trial. As John Phillips Dawson (1960, 2007 edition) says, the first judged courts we might recognise a little developed during the Early Medieval period. There is the famous example of Henry II of England sending his judges throughout the land, which was one of the key steps to developing (somewhat) independent law courts. Law courts in Medieval Europe were not expected to neutral or clearly independent, but they operate with some distinction from the Crown and could rule against what they wanted, or stay judgement instead of sentencing if they were unsure. Ecclesiastical courts were also existent and they were almost completely independent in Medieval Europe, which is why Henry II fought with the church with the whole Thomas A'Beckett thing". There is of course also parliament which developed over most of the Medieval period and the period before and immediately after the development of the Commons was when the Barons did the whole "Barons ramping the country from end to end" from time to time (as well as the War of the Roses when the monarchy and parliament were destabilised). The development in status of the Commons coincided with a more submissive and dependent Lords while the Commons got more bold with their growing status during the 16th century, but I digress. Clerks and ministers with seals were also a long running thing that required monarchs to work with others who helped them draw up their orders. The necessity of honest counsel was long recognised. It is also important to note that local grandees and town administrators did most of the day-to-day work of governing people up-close in the localities during the Medieval period.

Thirdly, a lot of people underestimate the significance of Medieval religion. The Latin church, the name from the Roman church during it's period of universal Western power before the Reformation, was an institution that unified otherwise disparate and potentially conflicting people. Popes often tried to promote peace treaties between Latin powers (and occasionally holy war against the infidels, cough cough). In day-to-day life the intercession of saints and the taking of sacraments was a hope spot where people could feel in touch with greater forces and structures looking after them. The parish church was one of the most important communal places and the signifier of neighbourhood acceptance, those guilty of offences against the community were excommunicated to show their rejection from it. The excommunicated were social exiles "Nobody else might join with him 'in eating or drinking, in buying or selling, in prayer or greeting" (Rosalind Hill, "The Theory and Practise of Excommunication in Medieval England, 1957) Hill points out that penance that was usually allowed to get back into the church after excommunications reconnects them with the community, The parish church and religion as a communal glue is what places religion in this role of communal regulation, which it took over from pre-Roman practises. It is worth mentioning that this communal element could result in a lot of distinct communal identities even within official uniformity (Gervase Rosser, "Parochial Conformity and Voluntary Religion in Late-Medieval England", 1990).

I hope this gave you something to chew on.