There is no permanent damage, so don't worry about that. Some people get very anxious about being off the medications since you relied on it for so long, and starting school can cause new anxieties. It sounds more like that than medication withdrawal which would have come sooner. Nevertheless, sometimes odd things like this happen, but shouldn't last more than another week if it is medication.
http://www.medhelp.org/perl6/MentalHealth/messages/C32713-10.html