I left the infantry to become a medic, but arrived to AIT and realized I hate it. Can I simply drop the course?

Could not have said it better . All the advice given above my comment here is coming at you from decades of experiences and commitment . Medic school and “Medic’in” are vastly different . I know first hand . I can tell you that the feeling of trust and brotherhood that is shared with you and belief in you shared by those you stand ready to serve as their “Doc” those feelings are deep and rarely come anywhere else in life . Once they see that you have earned the title “Doc” they will do anything for you and although part of your personal medic pride is that you jump your own gear , they will want to carry your gear , your meals anything to help because they see what you do for them and they are honoring you ... that’s the real deal , same reason (should be) that you enlisted , to help others , that’s what you do as a medic and it’s a great and high calling . Self doubt happens but kick it to the curb and focus on the task at hand do your best , get a study group and focus on success not the BS. You are there to learn the “basics” and to earn the chance to learn more after that course is completed . Don’t sell yourself short just remember they could do it , you can do it . Give it the respect it deserves and you will find yourself being proud of being “Doc”..
best wishes Doc Cheney