Will the pain ever go away??

After spending Monday night in the er for bleeding and cramping, my doctor confirmed yesterday that I am having a miscarriage at 7 wks 3 days. They said there is no heartbeat. I have not passed the baby yet, I am suppose to have a D&C on Friday. I have 2 step daughters at home 3 and 7. Tell him so heart breaking. My fiancé has been as supportive as he can. He doesn’t really understand how I feel. And I am trying not to let my sadness and depression show through. But I can’t help but feel like I am a failure as a mom, woman, and fiancé. Also a part of me wishes I would have never heard the heartbeat last week. Everyone keeps telling me it wasn’t our time, we can try again, it happens for a reason. I am so tired of hearing it all. I have never been so broken in my life. There are woman out there that have 5 kids and don’t want any of them. It’s not fair. And I know life is not fair but I wanted this baby so bad. How do I move on? When will the pain go away? When will I stop crying?