I'll let you in on a secret: almost everyone hits the limit in Calculus 2. For that matter, most people hit the limit in Calculus 1 so you were ahead of the curve. That doesn't mean no one understands calculus, or that you can't learn it. It just means most students need more than one pass through the material. For instance, I don't think I really understood integration until I learned numerical analysis and the trapezoidal rule in grad school.

There's a common saying among mathematicians: "No understands Calculus until they teach it."