Best friend breaking my heart.

I need some help. Please I'll take any advice good or bad. I am 18 years old and my best friend has been my best friend for 8 years now. I met her on the internet 8 years ago and we really hit it off. Starting this summer we started talking 12 hours a day non stop about everything we could think about. It's been 4 months and we have never talked less than 5 hours a day. At the beginning of this month I met her in real life and she was amazing. I had such a wonderful time with her and I could tell she really enjoyed it as well. Well anyways now when I talk to her she only talks to me while she does her college homework. She only responds with "mmm hmm" "yeah" "hahahaha" etc. And then when she has any free time at all she goes off and hangs out with somebody else. Dorm friends, room mates, etc. When she goes home for the weekend she tells me she'll talk to me but then runs off all day. She has alot of guy friends and I'm a very jealous person which I hate about myself. She runs off and hangs out with them for 8 - 10 hours a day while I wait here at the time she told me she will be back and I wait for 3 hours and see nothing. I get a horrible sickening feeling and I get depressed when she doesn't get on. She does this every week and I'm constantly depressed from this, it's breaking my heart. We tried going out but she dumped me 2 weeks later ( a few days after meeting her in real life ) because she wanted to "date other guys" But she has never gotten together with anybody else. She still wants to be my best friend but will not put any effort into it. I feel like I'm addicted to her but she so easily runs away from me. Why do I feel so sick when I don't have her to talk to? I literally spend all of my free time waiting for her and hoping she'll get on to talk. What is wrong with me? Should I seek professional help? Tweet