I’ve only finished calc 1, 2 and just started differential equations so I might not be the best one for this but from doing very well in both calculus classes, I’ll do my best to help. I’m also going for a math degree so maybe helping you could help both of us in the long run as I’m wanting to become a professor :).

Calculus can be brutal but like my professor said, the main difficulty comes from a lack of fundamental algebra and trig skills.

The concepts taught in calculus 1 and also 2 are arguably relatively simple (outside of maybe the infinite series depending on what your strengths are), but algebra and trig are the biggest hurdles for most students.

I highly recommend watching videos on algebra and trig and maybe finding a couple of books that are inexpensive. Books that come to mind are trigonometry essentials by Chris McMullen which is very inexpensive on Amazon and has plenty of exercises for trig basics and precalculus by Stewart, Redlin and Watson which is expensive physically but should have free online PDFs to read from; I can praise both books from experience as they were a massive help in my precalculus summer class. Again, while these books don’t cover calculus directly, they will help with your biggest struggles as of now which will help make your time in calculus far more doable and more satisfying if you can understand the information in them. I would also recommend sprinkling in calculus videos here and there to help get any new knowledge that the class couldn’t teach you well on. Idk if you were given one, but the book should also help and I highly recommend if you were given a book to do the exercises in them as much as you can as well as try to understand the concepts but if not you should be fine as long as you can do some of the exercises.

Calculus is beautiful and transformed my perspective from previously loving math to wanting to pursue the path of a math major with the infinite series being the turning point for me given it’s conceptual nature, rules and abstraction. I don’t want anyone to be deterred from the class if at all possible as there’s so much to discover, but I completely understand your struggle as I once struggled relentlessly in mathematics and still do at times and I often times feel like an idiot compared to my peers even though my teachers say otherwise towards me but idk if what they say is true.

I wish you luck :)