One of the most beautiful functions humans are built with is the ability to forget. To remove the pains and sorrow and sadness. One of the hardest things humans have to do is to deal with the hard situations. To accept, to forgive, to let go.
I'm sure you're down with that when I say the best things in life aren't always the ones that make us feel good. I've never walked in your shoe before, but believe me we've all been there, in a state where nothing seems to be right and the easiest thing to do is to blame, while it's actually no one's fault that life can be the meanest bitch and the best teacher at the same time. Life may cause you to wonder why it had to be you or why it happened to you. Truth hurts, that you don't always have the answer of all your whys.
But you have options. To keep the bad memories and make them a lesson, to prevent them to happen again. But if that seems to be too hard, remember that you have the ability to forget. You have that ability to leave what hurts and to make a new start. You have that ability to replace the memories you don't wanna keep with ones that are less bitter. And I know it's hard. But just because it's hard doesn't mean it's impossible. You'll be surprised to know what you'll get in return, for life sometimes has the most mysterious and surprising gift ever. Nothing in life worth having is easy.