Just started taking 400mg a day

Anyone else take this dose or progesterone pills orally? That seems like a high dose. First pregnancy I did suppositories. Got a blood draw at 4 weeks and it came back at 8. Also how long does it take to start working.

Any experiences or stories would be much appreciated. I’m very nervous about the whole thing.

Pamphlet with progesterone pills said do not take while pregnant, which also has me anxious. Pharmacist said it is fine if doctor prescribed and that they put that on lots of things.