Dear Grace:
Reads to me like there is nothing you can or should do about your roommate spending weekends with her boyfriend instead of with you. I understand your loss, being that she is your only close friend in Pennsylvania. But she has the right to spend her weekends with her boyfriend, just as you would have this right if you had a boyfriend. Therefore, I suggest that you don’t revisit the topic with her and accept best you can that this is how things are.
As far as your loneliness, you asked for tips about making friends in college. If you tell me how you tried so far to make friends, what worked and what didn’t work (and how you made friends with your roommate), maybe I will be able to think of something.
anita