hcg levels decreasing

I went to an urgent care clinic because I was having some light bleeding. I've had two miscarriages before this pregnancy, so I wanted them to check my HCG levels period I went back on Tuesday and they called me today which is Thursday and told me that my levels were decreasing and that I would miscarry. I also saw my OBGYN today and they did an ultrasound which showed it healthy baby and heartbeat period i measuring 10 weeks my having a miscarriage or has anyone else experienced this and had a healthy baby?