If you read my posts over the past two months you'll see I also went through a huge "what is wrong with me/why did I scare him away" phase post-breakup as well. After counseling and LOTS of conversations with friends I am finally past that part of it, but was also depressed for awhile. Dreaded waking up in the morning and remembering how things would be different, engaging in activities but not really enjoying them, XBF was in my thoughts like 80% of my waking hours, etc. After two months I can say that it's finally diminished, I enjoy things that I typically enjoy doing, and he's maybe in my thoughts like 30% of the time (which still sounds like a lot but is a big improvement, and it's mostly when things trigger it. For example, we had a webinar at work yesterday where the main speaker was in Canada, and XBF grew up in Canada, so he was in my mind for quite a bit during it). And I can better identify some of the red flags that I ignored in the spirit of being "open-minded" or felt like that was all I deserved or could get, but that I probably wouldn't have tolerated or put up with had I been at a different point in life. I was attracted to "edgy" and interesting (which really meant not dependable, elusive, and ambiguous) and hopefully I know now to not overlook the "boring" aka nice and dependable guys who actually have the values I want.
Time helps. Staying busy helps. I read some articles that talked about how people's brains right after a breakup look much like drug addict's brains - your brain is actually addicted to the person and when they leave cold turkey it's much like a withdrawal. Your brain keeps thinking about them as a way to feed that craving. Maybe knowing that much of it is brain chemistry right now is helpful!
Me:30 H:29, no kids T:12, M:4 (when D was final) 12/13: "Don't think I want to be M anymore" 6/14: Separated (I move) 1/15: H filed for D 5/15: D final