I am sorry for you. You should see a counsellor or a psychiatrist. What you are experiencing is due to the hormones produced in your brain. You will have to take medicines to regulate its amount.
I know it is very hard to overcome depression. However, we try to stand, we feel like letting go at the end.
The reason you suffered in your relationship is not your fault. He has been a bad lover. If someone is blaming another, The fault is the one who blames. I hope you will get good friends and be happy again.