Advice?? Pregnancy??

I’m pretty sure my last period was January 21st I was expecting my period around February 19th but it was missed for a week so I took 2 tests on February 25th both came positive, went for an ultrasound 6 days later it was transvaginal, couldn’t see a baby just a empty sac so we assumed it’s very early although the scan read it as 5 weeks and 1 day, I go on with my day and I start spotting brown discharge I was told it was normal and would go away after 24 hours, the next day it’s blood bright red almost pink, I was told to go to the er just in case and they took blood work and what not got told my hcg level on March 1st was 900 and on March 4 it was 3000 so the doctor said that was good and might be a sign of just very early pregnancy, that following day the bleeding slowed down and was more brown but I had what looked like clots. Should I be concerned or could it just be a sign of implantation bleeding as we aren’t sure what the dates are? What do you think?