Sorry to hear that. I'd suggest taking the class with another professor, some professors are harder than others. Just ask around and make sure you get the easiest professor. Since you are going into engineering I'm assuming you are talking about calculus. Calculus is only hard if you don't understand the basics sometimes is worth going back and reviewing past books on algebra. I hate when I know how to do a problem and I mess up on something stupid like adding or subtracting. Also make sure that you study with a group, it puts pressure on you to study. It kinda makes you compete with your classmates since you don't want to be the one that gets the lowest grade. Good Luck!