Progesterone decrease but heard heartbeat?

Kaycee

I’m 7w5d and we had a good ultrasound two days ago where we heard the heartbeat and I was measuring well. I’m concerned about my progesterone because it was 20, then 19, and now 16. I’ve been on prog suppositories the whole time. Has anyone had decreasing levels but a healthy pregnancy? I know hearing the heartbeat is a good sign but I’m still worried. TIA