Liz,
I am so sorry for your loss. Munchy is right you did nothing to cause this - unfortunatley nature does this when things aren't right - and i know how you feel, i thought it was my fault to - i thought that because i used to smoke or something - but like the doctor said to me - its nature doing its job - and at that time i hated nature. You need time to greive and just cry, feel it all, you will never forget but you will get better it just all takes time.