11 weeks pregnant spotting

I’m 11 weeks and 2 days and have been spotting for 3 days now. Yesterday I passed a quarter sized blood clot. When I passed the blood clot I had a back ache. I went to the ER Saturday night and they checked everything and said it was normal but to see if I’m actually miscarrying I have to go back in 3 days and they gotta see if my pregnancy hormones are getting less and that’s how they’ll know. I’m going in tomorrow but I’m just so scared. This is my first pregnancy and I don’t even know what to expect. I just need some answers or advice from someone that’s been through this. Thanks.