Basically my girlfriend and I broke up and went our separate ways since she felt that she didn't love me as much as she did when we started dating and wants to be friends when she comes back up for uni in August. We tried to talk it out but eventually decided to call it a day and break up but it left me and her completely devastated and we are both hurting badly (we ended up having breakup sex which which a very stupid thing to do and she asked if we could just be friends with benefits but not sure if this was serious or not). When I left she was standing at the window with her hand placed on the glass like something out of a movie and 99% of me wanted to go back inside and just hold her but I had to leave since it was hurting both of us seeing each other so hurt. I haven't spoke to her since we broke up which was just over a week ago but feels so much longer.
Since then I have had a really bad stomach and seems to hurt whenever she crosses my mind which is a lot unfortunately. It has also caused me a serious lack of sleep. I used to be able to sleep from roughly 10pm to 6am but now I only get about 2 possibly 3 hours sleep, if I'm lucky. I can't seem to properly concentrate on tasks either (unsure if this is her or lack of sleep) and can't stop thinking about her and if she is okay or not. I know I shouldn't but I can't help myself, I still care about her so much but I told her that I needed time to get over her and try and let my feeling for her fade away so I can't really contact her.
Any advice or anyone experienced a similar pain?