I assume this would be your first calculus class and that it's not proof based. In which case here's a website that covers 3 semesters of that mostly through worked problems broken down in a clear manner. http://www.khanacademy.org/math/calculus
Spivak is kind of an intro to proofs book. I would recommend starting with it. It doesn't assume you know anything at all and it sort of eases into it. Once you start limits there's a bit of a difficulty spike but once you start "getting it" the rest comes easily since limits are the hardest...
In addition to the above, for electromagnetic theory, the actual feynman lectures aren't a bad place for that. Volume 2 is pretty much a complete treatment of the subject.