Has anyone experienced extended (>100 matches) stretches of playing worse than you have previously?

I track my PR on Galaxy and my average PR over each 100 matches has been monotonically decreasing, until now, when in my last 100 matches I played a whole 0.5 PR higher than the previous 100.

Probably the answer is just that that 100 matches isn't a big enough sample size due to PR randomness (e.g., happening to get easier-to-play vs. harder-to-play positions).

But it's also possible that I'm playing worse and I'm annoyed that I can't figure out why. One explanation is that I'm overcorrecting and making mistakes I wouldn't have made earlier (e.g., before I missed a bunch of doubles, so now I'm doubling too early, or before I took too much and now I'm overcorrecting by dropping too much). But I'm interested to hear from people with more experience than me. Does 0.5 PR sound like approximately a normal size fluctuation for a ~100-match sample?

Yes, that's a very normal fluctuation.

My words will be maybe off concerning the topic. Also sorry for my weak english.

Last weeks i feel i play way worse than usual. Maybe 2-3 PR points differences.
I feel that i played and analyzed/studied too much, lacks the "gumption". Also probably concerning too much about the results, not the process.Maybe doing a break without backgammon is a good idea. I am going to think about psychological/motivation. Also once you start to loose the trust in yourself, it can take time to recover.

Concerning 0.5 PR differences, i think there is a lot of variance for the difficulty of the games, even in a 100 match-serie. That seems not a huge difference.