For me my anxiety makes all situations personal. What I mean by that is that I become very self conscious and self reflecting (ie. people are looking at me, is this person laughing at me?, i came into class a little late, did the lecture notice? etc) So automatically focusing on the work at hand becomes difficult. I tend to pick up little bites of information rather than being totally immersed with what is being said.
By and large I got away with it by having a good rote memory, which made it easy to remember theory and written work, without really having a great understanding of it. Much more difficult subjects like physics, calculus, civil engineering equations - I had no chance really. Those subjects need concentration and practice. I was so stressed out in uni that that became impossible and hence i had to give it up :(
Yes I panic too, and ironically wanting to be perfect and thus not failing actually lead me to failure
it is important to keep your anxiety under control. The best thing (although it is not easy for us anxious types) is to convince yourself that learning is not a challenge but a gift really. just imagine how dull your life would be without knowing the things you know, and how it helps you to think of more things than just yourself.