I CANT stop thinking about him even though we've hardly talked?

Long story short, I met a guy at a party 6 weeks ago. We began talking everyday, hanging out multiple times a week, going on great dates, etc. We both told each other that we really, really liked each other. Although everything was extremely rushed, I felt so incredibly close and comfortable with him (which I don't normally do). However, as of yesterday he is across the country until August and after we first met he made it clear that he did not want a LDR. Things went downhill and I got the feeling that he only wanted to be FWB. About 2 weeks ago he stopped texting me everyday. We didn't talk for about 3 days. I saw him the next weekend (1.5 weeks ago) and haven't heard from him since. Also, he straight up told me it was a call. I was so hurt and mad at myself for falling for it. I do believe he honestly liked me at first, but then decided that he would just use me for . Even though we havent talked in 10 days I can't stop thinking about him. Every time my phone rings I hope its him. When I get on FB I have to go to his page first. What do I do? This is making me so depressed.