Progesterone question?

Hi all, I've had an interesting time watching every little thing and had some questions on my situation. I had my first appointment today and from my last period I should be 9 weeks. I measured 8 weeks and showed a healthy heartbeat at 163 bpm, abdominal scan. The doctor was pleased and everything. I had bloodwork done and waited for the results, because I had spotting last week that was light brown for a couple days just when I wiped a few times a day. I feel like a lot of my symptoms aren't as intense since the spotting, but since I had a normal ultrasound it should be fine? I'm just concerned it measured a week behind, which is when I was spotting.

So with those concerns my doctor took my bloodwork just to please me, and I noticed my progesterone was 21 last week, but today it was 16. The nurse seems to think it is normal, but is this actually normal or should I be concerned? I've miscarried twice and just want a healthy baby.