I've had less trouble with Calculus since I saw it applied to real-world concepts. The classic case is the relationship between Distance, Velocity, and Acceleration. You can view Integration and Differentiation as more "general" versions of multiplication and division that you can apply to functions rather than just numbers.
If you drive at a constant speed, you can multiply your speed by the time you travel to get the distance you travelled. But what if your speed is not constant? Say you draw your speed on a chart versus, it follows a mathematical curve? If you have the function that defines that curve, the distance travelled is the area under the curve between the start time and the end time. You can do various things with geometry to roughly work out the area numerically, but Integration is an analytical method you can use to get the exact distance, by "multiplying" the function by time to get another function for the distance.
The thing they didn't tell me about Calculus is just how much of it there is to remember. At university I felt I was being examined on how much of it I could remember, rather than my skill in using it. Pointless, since out in the real world you don't get penalised for consulting a reference of some kind, since it's all about results, not being a swot.