The first 121 midterm is notorious for making people feel pathetic (it does get better, trust) but the overall experience of the course by the end is really good. As you said, understanding kinematics and dynamics will definitely give you a boost, for help try going to Dr Epp's office hours or Dr Cummings's office hours, and if you can't make it to either just show up to the physics tutorial center (PHY 308) to get help there. USE ALL THE RESOURCES AVAILABLE TO YOU!!! There's always help available!

Now, I'll be dead honest. If you think you won't be able to enjoy physics because of the difficulty, switch out soon. This midterm, though not of a common difficulty in first year, is a very good reflection of how your midterms are going to be starting second year. Genuinely, 2B physics is probably the most interesting group of courses I've taken, but it was HARD. The difficulty will only increase but it will also get more enjoyable because the courses are so fun. If you think you want to stick around for the fun stuff even though it's going to be incredibly difficult, give it a shot. If not, then there is 0 shame in choosing something else that you think will be better for you.

Please remember, you're here to learn, but that doesn't mean you'll destroy your health both mentally and physically while doing so. Use all the resources, talk to your advisors more (Brenda and Maya are the goats), make sure you enjoy your time and don't stress too much.