Progesterone levels

Chappy_jr

Got my second beta results just now and the HCG more than doubled (235 to 793)!!

However, my progesterone dropped from 18.8 on Monday to 17 on Wednesday.  My doctor says he likes to see at least 18 and has prescribed supplements.  

I don't feel like 17 is anything to worry about but the slight drop is a little concerning.  

I've seen a lot on this board about betas but little about progesterone. What are your levels/ your doc's recommended levels and is anyone else on supplements?