22 years later I still have nightmares about DiffEq because I received a C in the course when I really deserved an F. I’ve sometimes wondered if the dreams would stop if I sat down and successfully learned the material.
But 50 years later, I still have those gonna-flunk dreams.
Don't trust your teacher, read 4 different textbooks if that's what it takes to make it stick - it doesn't matter whether is dry as a desert or visual, just whatever works. The amount of intuition you have grows exponentially.
The rule of thumb that I live by is that learning mathematics is difficult, and teaching mathematics well is almost impossible - prepare before hand. I don't think I've learnt anything in a lesson or lecture post-algebra, that may not be the best thing but I have a very good feel for what I need to learn because of it.
I strongly encourage you to relearn these concept with OCW MIT with Strang and Moler [1].
[1] - https://www.youtube.com/watch?v=ZvL88xqYSak&list=PLUl4u3cNGP...
I think, I only passed because my discrete math prof told my calculus prof I'm not an idiot.
Anecdotically, I have this kind of nightmare at least once a year and I'm from Chile.