I think the biggest difference you would notice is that you are working a lot less (for comparison, a typical work year today is around 2,000 hours--also the methodology there is often a bit dodgy, but it is nicely illustrative). Pre-industrial labor is very difficult on the body and has periods of intense pressure and labor time (harvest and planting, of course, but also in case of any problem that may arise and needs to be fixed) but is not quite as day in, day out as modern industrial labor. It also wasn't nearly as regimented, with hours not really being set by the lord but by need and, thus, how the peasant assesses that need. The lord would instead take a portion of the produce rather than paying a wage for hours.

This is somewhat difficult to analyze historically but I've done a bit of reading on modern subsistence farmers (particularly "subsistence affluence" or those who grow for subsistence and comfortably manage it, Ernest Fisk coined the term as a rather surprised researcher) and it is pretty crazy the different sort of labor regimens people make when largely farming for themselves. There are areas in fertile Indonesia, for example, where the actual work of agriculture takes literally minutes to an hour a day because all that is required is shoving a bit of dirt aside and scattering some seeds (leaving them time for impressively complex handicrafts). And there are some places where the individual land use rights is a helter skelter scatter of plots so jumbled that a farmer will spend much more time walking between their plots than actually farming--all solvable by a bit of reorganization, which the farmers are fiercely resistant to.

Clark's Farewell to Alms has a brief discussion of this, where he places the change in work weeks to more structured and longer periods as sometime during the eighteenth century.

You might be interested in E.P. Thompson's classic essay, "Time, Work-Discipline, and Industrial Capitalism". Thompson argued that industrial capitalism and wage work fundamentally changed the way in which people in the West experienced time; shifting from a task-orientation, which ordered days and months according to the chores that needed to be completed, toward a time-orientation, which conceived of work as a commodity measured by minutes and hours.

One of the things he noted was that there tends to be a lack of urgency in pre-industrial societies; expressions such as "saving time" and "wasting time" are really the product of industrialization. As he put it:

Three points may be proposed about task-orientation. First, there is a sense in which it is more humanly comprehensible than timed labour. The peasant or labourer appears to attend upon what is an observed necessity. Second, a community in which task-orientation is common appears to show least demarcation between “work” and “life”. Social intercourse and labour are intermingled—and the working-day lengthens or contracts according to the task—and there is no great sense of conflict between labour and “passing the time of day”. Third, to men accustomed to labour timed by the clock, this attitude appears to be wasteful and lacking in urgency.

So according to Thompson, you probably would have not felt the same kind of pressure, although the medieval serf of course would have experienced all kinds of deprivations and hardships that would have made life unpleasant.