Good and Bady Days?

It is really annoying for me to have such varied days. Do you guys have this problem too? For a couple of days i will be pretty good but then i will have a couple of down days. I just don't understand why this happens. I know it has something to do with what i have been doing in the past couple of days. Do you think this resembles crashing? When i crash it is only for a few days before i am back to my baseline if i rest up.