Calculus is one of the great achievements of the human intellect. It's fundamentals were discovered by Newton and Leibniz in the 1660's through 1680's - long before computers, before calculators, before electricity. It is beautiful and powerful; it has shaped the world we live in and made possible much of our technological advancement. Approach it with the knowledge that it is a very special subject.
Some of the study methods which worked in high school will not work at JMU - and certainly not in your mathematics courses. In particular, you cannot learn everything in class from your professor. The pace of the course is such that the professor is only a guide on your journey. It is your journey. The main feature that distinguishes college from high school is that you must learn on your own, outside the classroom. Therefore,
The pace is too fast and the material is too deep for your professor to tell you everything you need to learn. Your time in the classroom is assumed by a college professor to be only a small part of the time you spend on the course. (Incidentally, "reading the text" does not mean just trying the homework problems and then checking back for examples when you get stuck. This will not give the depth of understanding to earn more than a mediocre grade. It means reading the entire exposition and carefully following the motivation and line of reasoning presented.)
Do some work on the course every day. Consult the course schedule, and read about what will be happening in the next class, so that attending that class will be useful. And work on the week's homework assignment from the start of the week. Do not get into a situation where you have to cram for an exam. The single most helpful thing before an exam is a good night's sleep.
It is extremely common (despite warnings like this) for students who have had some calculus before to coast along (under the pressure of other courses) thinking "yeah, yeah, I know that" and not to do the daily detail work required. Then at some point they find that the ground under them has slipped away. They discover that the level and depth at which they are expected to understand things is different than it was in high school. The course has irretrievably passed them by and they must settle for a grade and a quality of understanding which is lower than they had hoped.
Students are here at JMU because they have been very successful in the past. Often they have gotten where they are because they are extremely independent. Such independence is invaluable, but in a new and more competitive environment it must include an awareness of when one is in trouble and the strength to ask for help.
First, try intensely to understand the material or do the homework yourself. Then, if you find you are having trouble, consider using the following sources of help: