I recently wrote that I had cystitis. Today in the morning instead of …

I recently wrote that I had cystitis. Today in the morning instead of discharge came blood. My cycle is 30/35 days as usual, but today is day 24. I went for an ultrasound immediately because yesterday night I drank tea from NL Don Bela. They told me there's something in my uterus to say pregnancy by calculation doesn't match as the ultrasound shows 5 weeks and 2 days but doesn't match with my period. Either it's a polyp. I did a test negative even faintly not showing. Has anyone experienced this? Were polyps removed? By the way, she also said that it seems like there's a heartbeat too and I heard it but I doubt it.