Firstly you need to get your stress levels evaluated. Memory and concentration may be affected due to Psychological issues such as depression. I would suggest you to consult a psychiatrist.

First of all to know about your academic achievement. I would like to rule out anankastic trait with social phobia. In anankadtic trait people are very particular to certain things like things should be in proper order and should be neat and clean and atmosphete for reading should be silent not disturbing. Due to social phobia one can have difficulty in getting  concentrate in group talk . Besides that anxiety  may also be playing its distracting role. Anyway consult a psychiatrist to discuss allthese things as per my advice.