I feel like im losing my friends?

[Bob]

Its my second year at university and i feel im losing everyone im close to. The first year i had so many close friends and well all had similar interests, we all wanted the same things and we never felt we needed more than what we had. Now as a second year, everyone has went in a different direction for no special reason. I still have my best friend, but week after week i feel more and more disconnected. Ive opened this subject with my bestfriend several times, and she denies that its true. Can someone explain whats happening? And can i get tips on what i should do? should i go out and do my own thing or should i try harder? is it my fault or is it normal for this to happen. Thank you in advance.
Were all in the same major btw