Encouraging thoughts? Success stories?

So pretty sure I miscarried today at 4 weeks. I've been bleeding all day. Go to the doctor tomorrow to confirm. My levels were very low Tuesday. HCG 15 and I think my progesterone was around 2 and they said it's supposed to be around 12.... Not sure what caused it. I was on depo up until a year ago though. Has this happened to anyone else? What will the next couple weeks be like?