Cramps and light spotting? Approx. 4 weeks 4 days

So I got a BFP 3 days ago and was really excited. I've been having mild to moderate cramps since then (honestly I think since the day before I got the BFP). Yesterday I woke up and was having some brown discharge/light spotting, and since I had the cramps as well I panicked and went to the emergency room. I got a blood test (HCG level was 375) and an ultrasound (they couldn't see anything yet, but thought it was too early). Also, my cervix was closed, so that was a good sign. The doctor concluded it could be an early miscarriage, an early ectopic pregnancy or just normal signs of early pregnancy. I have a follow up with my OB/GYN tomorrow. I'm pretty nervous but trying to stay hopeful. Anyone have a similar experience that turned out to be no big deal? Thanks everyone 💕