How do you get over a miscarrage?

I found out last Monday I had a miscarrage. I cried to the point there I had a panic attack and thought I might pass out. after I spoke to my husband I seemed to let it go pretty quickly. wrong! I have been hiding my emotions for sometime because he has been going through a lot so I think I just mask my feelings. but now I'm absolutely depressed and so sad. I go over and over in my head about what I could have done wrong. I blame myself over and over again. I don't understand why this happened. my sister is pregnant and i am so jealous. I see a pregnant woman and I just want to cry. my heart is so heavy and I can feel it in my throat. How long does this last? damnit I am so freaking sad. I wanted that baby so bad.