I still have feelings for this guy?

Well, about a month ago we used to talk ALL the time. And then finally one day he asked me out and I had the BEST weekend I have had in a long time. We talked over 301 minutes on the phone which is my record. I liked him so much. But then when we came back to school, over time he just started to fade away and I tried so hard I called everyday to talk to him but it just didn't seem to help at all. So then I just decided to break up with him. But I still have total feelings for him because he was really special, he KNOWS I still like him. And recently my "bestfirned" flirts with him and hugs him and it bugs the hell out of my because I mean cmon, shes a SKANK. She's gone out with countless guys. I'm scared. Any advice?