I will not be discouraged!

Went to Spin class tonight with the intention of doing my typical Monday night back-to-back classes. About half way through my first class I started getting some twinges of pain in my left knee. I decided against doing the second class and I continued to experience pain as I have been walking around this evening. I am not going to get discouraged! I don't know what is happening, but I will find a way to continue my fitness efforts. I intend to talk to my doctor about what is going on. As long as he doesn't tell me I have to stop cycling like he told me to stop running.