Find some good grounding techniques to help you stay in the here and now---and not in the future where you conjure up impossible to handle scenarios. 
(Some are sticky posted on site)
Make a list of things that you WOULD like to have when attending college. Once you're there, talk to a professor or your counselor/advisor about finding what you seek. Sometimes joining a particular group that meets on campus will work.
Realize that many of the college attendees are quite immature and not very focused. (Just met a few thousand of them for the Orange Bowl btw.) Find some key phrases to use to let them politely and nicely know you're not there for gossip and backbiting. (Sorry, I really don't know the phrases to use these days.)
Meditate. Breathing is huge when it comes to anxiety attacks. Usually when we panic we hold our breath, making it worse.
College can be a great experience! Seek out what you want and leave the rest behind!