I miss her so much... It feels like i'm dying. I don't know what to do, please help?

I met this girl online 3 years ago, we became Very close, talking to each other all day ect. But were never more then friends although we both had feelings for each other. I fell in love with her. We both lived in dif states, 1800 miles away. I moved there to be her roommate in february to help her out. We had alot of differences but i was still in love. I had to go back home to my state last week to preship for boot camp which i leave august 1st. She told me while i was leaving not to wait on her, i deserved someone better and she doubted we would ever be together. It tore me apart. She had a 2 year old daughter too that I loved like my own and I miss the kid too. Now i'm back home, waiting to ship, she works alot and we can never really txt or talk now, and she pretty much cut all hope for a future together. I'm losing it, i cant eat, sleep, it feels like im drowning and have intense heart pains. I cant get her out of my head i miss her so much. Shes my first love, I wanted to spend my life with her :(