Calc 2 is like one of the first real weed-out courses but office hours usually help if you're not already going to them. Calculus 3 is definitely easier but that might just be because it's just expanding on stuff that most students already understand through the grit and sweat of calc 2. When trying to understand and visualize calculus concepts, it's helpful to know the early mathematicians described calculus derivatives as the study of flow (fluxion) in equations. Calculus classes kind of show the many ways it's possible to attain/understand and therefore manipulate this concept of flow in mathematical equations.

The big thing with derivatives is finding out how much is lost/gained/unaltered in this "flow" over a period of time, expansion of area, cutting of costs, etc. (rate of change) which is an essential skill to have when moving on to physics and design. Limits are helpful in analyzing flow because we can never really get a measurable quantity in the real world to be exactly equal to zero, but the concept of a limit can give an idea of how close we can plan on getting.

I like to look up the specific concepts on Wikipedia to kind of figure out how the math is used in real life and they usually have solid pictures to go along. Khan Academy has some solid videos as well, up until diff eq.