Bleeding but still a heartbeat

I am currently 7 weeks and 2 days pregnant. I had heavy cramps late last night that went away by morning. At 4:30 this afternoon I started bleeding. I filled up one pad with slightly pink blood. No clots and nothing after that one pad. I went to the ER and they ran numerous tests, did and ultrasound and found the baby was still in there, with a heartbeat! My levels are still really high and my cervix is still mostly closed. Any ideas on what could be going on? I know the likely answer is a miscarraige but I've been laying here for so long and just want some advice or input. Thanks ladies. Xx