I am in the same boat as you right now. I have found that really the most important thing in this situation is to have someone you can talk to and check in with, and I feel this way very strongly when any girls goes into a non jewish college or a college that is not alligned with their hashkafos. If you have a teacher from high school or seminary great! If not, please do not think you are a lost case! Pick a good solid neighbor or family friend! I know I decided that I wanted to talk to my teacher once a week even if the week was uneventful. Obviously things come up on both ends and often its a little bit less often, but it is still great! And I can almost guarantee you that if you have a solid person that you keep up with so many of these issues really fall into place and you just find yourself being kept on track even if you were not before! Its a hard place to be sometimes, but give yourself the tools to let the situation strengthen and not bring you down in any way!
Good luck!!!!