Need opinion !

I tested at on Monday July 5 I was spotting bright red then it turned into brown the next day. I’ve been spotting ever since I believe it’s been like 5/6 days now .. I went to the doctor they said I could be about 5 weeks pregnant I went to the ER they said they couldn’t trust an at home pregnancy test my appointment isn’t until Monday. So they can do a pregnancy test and an ultrasound but today I started bleeding that amount! It looks like darker blood now I’m so worried could this be a miscarriage? I’m so scared and sad. :/ has this happened to anyone ? Please let me know .