Progesterone Dropped but HCG rose

I am 5 weeks pregnant (shortly after a miscarriage which ended at 5 weeks). My OB is monitoring my levels. My HCG levels were quadrupling at first and now more than doubling every 48 hours, however my progesterone has dropped from 26 last week to 16 this week. My HCG went up from 666 to 7,300+. My doctor is not recommending anymore bloodwork, or progesterone supplements. She said "everything looks GREAT, see you at your 8 week appt." After reading online I'm a little worried that I should be on a supplement for the drop. Anyone have advice or experience on progesterone? Anyone recommend I buy the cream and treat myself?