extreme fear of SIDS help!

My daughter is 5 months old, and Ever since she was born I have been absolutely TERRIFIED of losing her to SIDS. I don't even understand how it happens and I will literally not sleep just to watch her and make sure she is still breathing. Recently she started rolling on her belly and I have woken up to her Laying on her belly, even tho we put her to sleep on her back. Do you know of anyone who has experienced SIDS? I guess I'm just looking for some good, first hand education. 😕