Feeling discouraged

I just finished the first semester of my sophomore year and I received a D in chem 1. It wasn’t till this semester that i’ve decided that I want to be a pa. Chem 1 is the first pre-req course that i’ve taken towards becoming a pa and now i’m not sure if it’s for me anymore. I haven’t started any PCE hours and my school doesn’t allow course retakes unless it’s an F grade. I also can’t take bio 1 unless i’ve received a grade C- or higher in Chem 1. I’m just overthinking everything and I just don’t know what to do. I’m thinking of changing my career trajectory to something else in the medical field but i’m simply not sure anymore. Any advice would be greatly appreciated.