It depends on what you mean. Many scholars, myself included, shy away from the term "antisemitism" as it implies a racialized understanding of Jewishness not yet in operation. Jews were usually found in their own communities within or near Christian communities, to whom they were subordinated. And as David Nirenberg showed 20 years ago in his Communities of Violence, even in peaceful areas, Jews were subject to regular low-level violence, such as beatings during Easter. Occasionally, as in the Rhineland during the First Crusade, this low-level violence might break out into full-scale anti-Jewish riots and murders.
The received medieval view of Jews in the middle ages is from Augustine, who declared them to be left as subordinate to Christians but unharmed, forced to witness the power and success of the savior they refused to acknowledge. Nine hundred years later, Bernard of Clairvaux would call on Augustine in his defense of the Jews and suppression of another wave of riots during the Second Crusade. Recent work, specifically David Frick's Kith, Kin, and Neighbors, has drawn the distinction between tolerance (i.e. multiculturalism) and toleration (i.e. grudging acceptance). In this schema, Jews were tolerated, but Christians did not practice tolerance.
Christians did not generally think of Jews as heretics, because heretics preach false Christian doctrine. But, starting in the twelfth century, as Christian scholars took a renewed interest in Hebrew texts, they discovered that contemporary rabbinic Judaism deviated substantially (in their opinion) from that described in biblical and patristic texts, and occasionally leveled the polemical (but not formal or canonical) charge of heresy against Jews.
Anti-Jewish sentiment was fairly widespread. There were a few important things to keep in mind that made this so pervasive. First, Jews were simply the minority group in Medieval Europe. Obviously not the only minority group--there were religious and ethnic minority groups floating around. But Jews were a substantial minority across Europe over a long period of time in a way other minority groups simply weren't. Second, Christianity at this period conceived of Jews as being diametrically opposed to Christianity. Theologically speaking this is quite an easy dichotomy to set up. Jews had rejected and killed Jesus, Christians had accepted him. But more than that, Medieval Christians often concieved of Judaism as being everything that Christianity wasn't. Perhaps the best illustration of that is in the Ecclesia et Synagoga (Church and Synagogue and Judensau artistic tropes from Medieval churches. These contrasted Christianity and Judaism. Judaism was old and obsolete, Christianity was not. Jews were downtrodden and weak, Christians were in charge. Synagogues are placed of blasphemy, churches are places of truth, and so on. With religion being such an important part of life it was easy for these sorts of messages to pervade people's consciousness and think of Jews as being totally the opposite of them, with nothing in common.
Anti-Jewish laws and measures were quite common. Jews were a legal category of their own, not legally or socially intermixed with Christians (this was not necessarily disliked by Jews, since it afforded them a high degree of communal autonomy). Jewish communities usually existed at the liberty of the local king, under some sort of community "charter", which outlined their rights and legal restrictions. But more important than that was the social position this put Jews in. Basically everyone had an incentive to want the Jews out. Kings wanted Jews around mostly in that their skills and social position could be helpful for the economy (having merchants and moneylenders around could stimulate trade). But, both nobility and royalty could be jealous if Jews were too successful at this, amassing too much money. At that point they would be tempted to more strongly repress the Jews, to confiscate their wealth or cause their debts to Jews to be annulled.
FYI, you may find additional information of interested in the FAQ: there are several threads which address the Middle Ages
Note that the posts have been archived, so if you have follow-up questions for any of the users, ask them here and tag the username to notify them