How do I[19/M] stop thinking about her[19/F]

Girlfriend of three years just ended it on our three year anniversary. Says it's not for anything I did. Says she still loves me but she just needs to find herself, become her own person, not just be "us". Perfectly reasonable, we got together when she was 16 and I was 17. We could both benefit from this. I try to be as supportive as possible.

We tried being friends for a few days but it didn't work for me. I love her too much to just be her friend. Every time we're together it's no issue, but when she leaves and I have to hold back an I love you or a kiss I feel so empty and devoid of any positive emotion. And it lingers for the rest of the day. It's like I'm leading myself on. It's like breaking up over and over again.

I couldn't keep living like that. So I decide the best way to handle it is to stop being in contact with her. I explain and let her know. She agrees to stop talking to me. I say goodbye. I tell her not to contact me if she doesn't have to.

I'm broken. My mind, my heart, my body. I can't sleep, eat, or move. She's the love of my life. I say that truly and without hyperbole. She's the only woman I could ever think of spending the rest of my life with. The repercussions of what I've done have hit me and I feel despair beyond anything I've ever felt. I'm finding it hard to convince myself I will ever be as happy as myself as I am with her. I would drown myself in my work or hobbies but neither carry any weight or are able to distract me from the pit in my stomach. I'm utterly pathetic. If anyone else has felt this please tell me what to do. I can't keep living like this.