Why?

What happened when I skipped 2 weeks of Body Pump class? Legs shaking during yesterday night's back track. My legs was a bit not the usual form during Squats but I didn't give much thought to it. The back track is not even a tough track as we're doing 'Why'. My right leg started to wobbled during the start of the track and both legs were shaking madly towards the end. Gosh~ I told Marcos my legs were shaking after the class and we laugh about that. Didn't joined RPM after that as I wanted to rest my legs for tomorrow's classes. Hopefully I can get back in shape next week to do some back to back classes.