my doctor just prescribed me this, but never clarified If i should be worried or not, or what it's even for...😓😢

I had my first ultrasound last week at 5 weeks. They could only see the gestational sac and the egg yolk, but no baby. My doc left me a voicemail stating he called me in a RX, But never mentioned what it was for, or if I should be concerned. Not to mention, it requires a prior auth from insurance, so we paid out of pocket, thinking we desperately needed it. It was $430, and CVS had a coupon, and got it down to $247. We are boke, but need to get this rx, we are assuming. Anyone ever heard of it or know what it does or if I should have any concerns about miscarriage? I cried, and cried out of fear. Here it is...

thanks guys 🤢😢