Prometrium AND estradiol?? Newly pregnant

Hey ladies, so I'm 15ish dpo and we just found out we were pregnant on Monday (roughly 9-10 dpo). My hcg levels on 13-14 dpo were at 69, the nurse said that was good and in the healthy range for that early, but since I have a history of miscarriage, my doctor put me on 200mg of progesterone (prometrium) 3x a day and 2mg of estradiol (estrogen) 3x a day as well. Has anyone ever heard of these being prescribed together?? I've heard of the progesterone, and was prepared to be prescribed that as I'm estrogen dominant and I believe my last miscarriage was actually because my progesterone levels were super low. But what's with the estrogen? Anyone heard of these being prescribed together? Thanks girls!