Scared over mc

I was pregnant with our first baby. From my lpd I should have been 9 weeks. We have been ttc for years now so the news was a miracle. Then everything began to spiral out of control. My hcg levels were never high enough for nine weeks, I was only at 229 then I dropped to 149. Progesterone levels were to low as well. Today the bleeding has begun. The pain is unbearable and I didn't expect it to be this horrible. I know I'm not alone now but I am blaming myself for the loss. I keep thinking if only I did this or that. How do you get over the guilt? Also what else should I expect with mc?