I regret my MS so bad

So for context, I am a third semester grad student, attending part time now. While I currently have a 4.0 and am almost halfway through, I am in a really difficult class this semester, and IDK how I am going to do well in it. Last year (my first semester of grad school), I completely switched what I wanted to do with my life, and now my MS is serving zero purpose. I have my undergrad in bio and always had the intention of going into the healthcare field but I put it off bc I never thought I was smart enough to go to med school, hence me starting my MS. Well, I think I screwed myself bc even tho I had a 3.9 in undergrad, I am extremely anxious about my GPA dropping and not getting accepted to med school bc of this master's program. And obviously I can't drop out bc that would look horrible on my app. I feel so stupid for even starting this, before I started school I literally used to get nauseated at the fact that I left my dream of becoming a doc to become a biostatistician. And during my first semester I used to get physically ill going to class, thinking this stuff was going to be my career. And I am so happy I realized that and changed career paths, but now I am just so anxious that it'll prevent me from getting into med school if my GPA drops. This MS is literally harder than the MCAT, which is so absurd to say, if anyone is familiar with that exam.