Progesterone after spotting (8 weeks)

My doctor prescribed 100mg of progesterone for me to take daily until 10weeks because my progesterone levels are very low (6.2). They’ll check my levels again next Tuesday at my next ultrasound.

My issue is that after I saw her Tuesday and saw the heartbeat (which was low) I’ve been spotting more. And TMI, but there’s been brown spotting mixed with brown stringy stuff. It looks like the beginning of a miscarriage to me. I’ve also had that achy feeling in my lower back that preceded my previous miscarriage.

I told the nurse on the phone my symptoms today, after she told me my Hcg levels are rising and wanted to know if it was even worth the time to take the progesterone. She said I was probably spotting after the ultrasound because that’s normal. (Also I was in a building lobby and not able to describe everything for her in detail over the phone). Not sure I’m as optimistic as her.

What has been your experience with progesterone?