How do I move on

My boyfriend broke up with me, I know this happens to everyone, but I feel so broken. I was ready to uproot my life to be with him. I wasn't the best girlfriend, but he gave me a lot of hell and I stood by him and now that I need a chance, he won't give it to me and is done for good. How do I deal with this resentment and move past it? Do I need to see a doctor or therapist?? Is something wrong with me? I can't sleep, I can't eat, all I can think about it everything I did wrong and how I can do nothing to fix it.