2nd miscarriage

Hubby and I found out Dec. 27 we were expecting (odds were so low we never expected it to actually happen and were super happy). New years day we sadly miscarried and I was devestated. We have a 4 yo little girl who is our world and didn't feel like we needed to try anymore but the pill makes me absolutely sick and we figured we would just let nature take its course. I miscarried yet again this past week and now feel even more like a failure. What am I doing wrong?? Why won't they stick? My husband is wonderful and so sweet but he's not being very supportive. :( just need a hug.