From a CS background, several people I know have raved about the following book[1], of which will be friendly and useful for future needs anyway in the field. The first part of the book is what appears to be a pretty good refresher path.

IMHO working through that book will make you practice with enough basic calc to make moving on to stochastic calculus fairly easy.

[1] Performance Modeling and Design of Computer Systems: Queueing Theory in Action - Mor Harchol-Balter

https://www.cs.cmu.edu/~harchol/PerformanceModeling/book.htm...