Chess fatigueness and recovery? I have been playing chess for almost two years now and my playing strength revolves around 1000.

Quite often every month or so, i play below par and drop to 900's and never been consistent. I dont play to win, i enjoy playing chess.

What is causing this? Am i playing too much chess?
Having some fluctuations in rating is quite natural and not something I would be overly concerned. At your rating level blunders are very common, so that games are to some extent not decided by apparent playing strength (=rating) but by a random process and this shows in your rating fluctuations.

However, with your approach (for fun) to chess you should not be worrying about ratings at all and just enjoy playing.

If you do want to improve your chess there are many ways and even a little work will have a large impact on your playing strength at this level. For suggestions on how to improve see this question and answers.