They don't sound like they were very good friends in the first place. To be honest, unless you were exceptionally close, I don't see you maintaining friendships with them throughout your life. Also, university is a time when a lot of people try to forget their old selves and make a fresh start, become someone completely different. My friends are all at university and at first were not in touch at all, but now I get regular emails and I know that they are excited to see me at Christmas. I think that's how you know that you have a true friend, that you can be far away from them and know that they still care. I'd forget your old "friends" and embrace your new ones.