What should i do?!?!?!?!?!?!?!?!?!?!?!?

I like this girl and she knows it.. A couple of weeks ago she decided to say yes to this other guy when she asked her to be his girlfriend. she said she liked him too. I got really upset and told her i was done with her. when i went to pick up some of my stuff, i did and not a word was said.. i felt bad went back to say goodbye to see her sitting on her doorstep crying. i couldnt say goodbye and told her we were still friends. but thinking of her going out with someone else just tears me up inside. Then again so does the thought of her crying. She tells me she loves me and cares for me all the time and i just dont know what to do.....