I've been working through Spivak's Calculus for a few weeks; however, I am stuck on Chapter 5 (limits, epsilon-delta, etc.). I'm finding that I need to reference his earlier chapters (on inequalities) to follow the introductory proofs. Furthermore, I don't understand how he comes up with his methods for proving the theorems. Ideally, I would like to just 'grind' through the difficulties, but I am pressed for time--2 months+other daily activities--to learn the topics covered in high school BC calculus (AP curriculum). Due to these reasons, I am considering switching to another text, Art of Problem Solving Calculus, and coming back to Spivak later down the road. Based on my situation, would you recommend staying with Spivak or switching to the latter text?
A bit of auxiliary information: Spivak is my first introduction to Calculus; I need to learn BC calculus because the course I'm taking following the 2 months is multi-variable calculus.