Dear Tanya,
Your question reminds me of my own experience in college. I was an A and B ME student getting Cs in physics (the class average) and wondering if I should change majors. I didnt enjoy the classes and wondered if I was actually retaining many of the concepts. I stuck it out though, because I really enjoyed the math, other science like chemistry, and the heat transfer/fluid flow classes. I then went on to graduate school for a MSME and started working for a chemical company after graduation. As an aside, some people are surprised to learn that chemical companies hire about as many MEs as they do ChemEs. Ive had the opportunity to work in many different roles at my company, and the important common denominator for success is engineering logic and problem solving.
Dont let some tough physics classes change your career path if youre enjoying the other ME classes. More of it will stick than you think, and very few people are good at all aspects of mechanical engineering its a broad profession! Good luck with your classes
Best Regards,
Stacey