Anyone have heavy cramping at 5+5??

I found out I was pregnant with #2 the day after my expected period. From lmp (sept 26th) I’m 5+5 weeks. The morning of the 31 we had sex, immediately after I had bad cramping, felt flushed and thought something was wrong, 3 hours later I had dark red blood in my underwear so I assumed start of MC. Called doctors and was booked in for bloodwork, an ultrasound and a transvaginal. Tech said she couldn’t see anything but I was 5 weeks that day and she said it was likely they wouldn’t find anything anyway. Yesterday I had a second round of bloodwork done, and am waiting on results today. The brown has slowed down to almost nothing but yet again this morning I had horrible cramps (could barely stand up straight) actually almost went to ER. Within half an hour the pain subsided substantially and now I’m left with a dull ache and more questions than answers. Anyone have a similar story? Thanks

UPDATE: by 4:30 I got a call back from the doctor, my levels tripled between Friday and Monday, but he said they seemed a little low Friday, for how far along I’d be. I called my mom right away and as I was making a coffee and chatting with her, I felt a gush. It was very red blood in a fair volume. So I’m not sure what’s going on now, still bleeding.