I have signs of bleeding between menstrual cycles. I had an ultrasound and the results were: DAP # 31mm, peritoneum # 8mm, little cul-de-sac fluid. The doctor diagnosed me with inflammation. Is bleeding between menstrual cycles dangerous?

I tested the pregnancy test and it showed 2 lines, 1 dark, 1 light, but 2 days later I got my period. So doctor, can you tell me why I tested with 2 lines but still got my period?