4 weeks 5 days pregnant and bleeding with clots?

I went to the ER last night because I had started spotting and as it got worse I had back pain as well. They did an ultra sound and l probe and could find no baby; although they said it could be too early. They took blood and said my Hgc levels were low. The doc couldn't tell me either way what was happening. My cervix was CLOSED so that is a good sign but today the bleeding and clotting continues - with no pain. I have a follow up with my doctor next week but I am a nervous wreck. Anyone have anything like this happen to them?? Could the l probe and catheter cause bleeding?