Help

I had gone to the emergency room on Sept 2 because I thought I had a cyst the cramp I got felt absolutely terrible but when I got checked for a ultrasound they said everything was completely normal. A week later my period didn’t come down normal I was spotting so I took a Pregnancy test and that came back Positive. I went to the the emergency room again cause I felt cramping and my discharge was pink and brown . They took blood and they told me my HcG is at a 50 . The ultrasound was normal again … the next day I took ANOTHER pregnancy test and it came out positive. Still some cramping but the bleeding stopped. And it wasn’t as bad . When I went to my OB she said everything looked normal but she thinks I’m 4wks and it early but I’m really worried about these cramps . Do you think it might be ectopic ? What is your ectopic experiences ? What should I do ?