Any advice on how to not stress myself?

Last night I went to the ER cause my stomach was hurting so bad and I had started spotting blood I was in so much pain I could barely walk(sounds like labor lol)I had got an pelvic exam and a u/s and found out I had lost one of my babies.I knew that carrying mono-mono twins would be difficult.This is the crazy part because at my u/s in my doctors office I would be 15wks now but there in the hospital I was 19wks.I was shocked and I told the lady and she said somebody was not doing their job right but I was confused.My stomach is hugh I look like I would be about 6mths maybe 7and that explains alot.Every since I got back home I cant do anything but think about the baby that I lost and stress.I know its not good but I cant get if off my mind and I'm sad.I also have an apt on thursday with my doctor so I'll find out more about what happened and why am I ahead 4 wks.Any advice would be great. Thanks