Several Months Ago I Had To Watch My Mom Pass

Several months ago I had to watch my mom pass right in front of me, I was doing CPR on her till the medics arrived and told me they would continue. I take Valium 5mg 2 times a day and I also have crohns Disease but I just can't get that night out of my head, I re-live that night every second of every day. Maybe I should have done this, should have done that. Maybe I could have saved my mom, I don't know. How do I cope and move on, I feel like that night my mom passed was my fault. The stress of everything has me ready to jump off a bridge...oh and the stress affects my crohns in a horrible way. What should I do?