Low progesterone

Hey ladies. I was told I was pregnant from July 3rd. Levels were 5.4 (15 dpo) to 7.8 (16 dpo)to 18 (18 dpo). I know the levels are are quite low. Unfortunately I started bleeding like a period with cramps and clots. My progesterone dropped from 8.8 to 3.4. I have been on suppositories this whole time since I've ovulated. Why is my progesterone still low even with medication? What can I do to increase it? I'm guessing this pregnancy is over so what can I do next time? I waited 8 months for this only to not be able to carry it. 😭