Spotting/bleeding

So around 5 weeks I had spotting for 3 days. It was light pink.

Then at 6 weeks I had more spotting 2 days after we had sex. It lasted about 3 days.

I went to the doctor yesterday and saw the heartbeat. I’m 7 weeks according to LMP but I was measuring 6 weeks 1-3 days.

So today I am bleeding again. It’s light but it is red.

My doctor told me yesterday it’s not coming from my cervix and it probably just from having sex.

So is today’s bleeding from my ultrasound? And why is it red now? Freaking out. Any advice?