I have to say I agree with Kirby Smart above. These are some of the easiest pre-med courses so it's just going to get harder from here on out, and med school will be even worse. Here are some things I would think about if I were you -- not asking that you post the replies but more of suggestions for you to reflect on personally.
-How are you studying? Are you actually putting in the time or was it a matter of not doing the work? Or maybe it is that you are studying ineffectively? Or, are you a smart kid who didn't really have to put in the work in HS so maybe now you don't know how to study? Although some 101 humanities classes can involve studying facts (such as history), usually the approach for science/math studying is different than humanities studying so the divide here isn't necessarily surprising. Consider meeting with a study center, tutor or learning specialist at your school to help evaluate this type of thing.
-Did something happen this year that played into how much effort you were able to put into the science classes? If so, maybe consider counseling to help learn effective coping skills, and/or think about an LOA if you need it.
-Why do you want to be a doctor? How important is it to you? How deeply have you looked into the career and really thought about whether the time, money and stress investment will be worth it? Have you ever considered other careers (inside or outside of medical careers)?
-Have you ALWAYS struggled with science? (How did you do in high school and did you take honors/AP classes or just regular classes?) If so, this would be a strong factor to me in terms of reconsidering pre-med. Sometimes being on the struggle bus the entire road to your career is not worth it. Flip it on the head and make it a positive. Maybe your strengths lie in the humanities? What are you GOOD at? What are your talents? How can you use those to find a career you can excel in? If you don't know the answers to these questions, maybe consider meeting with your advisor, a professor you get along with, an older student friend, or your school's career center to help you figure that out.