Tap class is killing me

I have really been enjoying tap class over the past eight weeks, but suddenly tap class isn't as fun. I say this because as I type I'm lying in bed basically incapacitated. My back (the one I would seriously like to replace) is so tied up in knots that I'm crooked...again. It's happened before but so far this tap class has been fine. But today I lie here in bed completely crippled, and yesterday we had a sub on class. Guess her amped up tap class isn't for me. Guess I need tap for seniors or low impact tap. Yikes. Glad our regular instructor will be back for the last class.