Ugh, I get similar kinds of things when I'm under too much stress. Sympathies; it's so fucking annoying.
Your mouse movements and where its corresponding cursor shows up on your screen are out of alignment. Re-calibrate.
Meditation can be neat for that, actually, if it's the whole thing of 'body. body. we're not that stressed. why do you think we're that stressed. why.' You mentioned feeling extra tired or having upset stomach as the kind of thing that pops up - I know this can sound super elementary, but not eating enough or not sleeping enough can also lower your hallucination threshold. As can any sort of Body Thing which might need checking out by the doctor - a couple symptoms that tend to fuck with me are pain flares and low blood pressure, so even if I'm not mentally stressed out, my body is still like NOPE. WE ARE DYING. TIME TO HALLUCINATE. So if you're in a position to check for possible somatic problems, that could help. I always advocate frequent naps. :P Often for the same reason as meditation - helps clear your head, as well as clearing up any sleep deprivation issues. I tend to feel like my head is overloaded and fuzzy and has a million things overlapping each other in these sorts of situations - I don't know if that applies to you at all, but for me what helps there is to find something that can be completely absorbing (often video games, because sight + sound + hand movements + so on is a good way to completely occupy my brain) and only focus on that one thing for a bit, and that helps pull my brain back together and stop shooting nonexistent echoes at me for a bit. (It's also worth checking in with yourself to see if you think 'the appropriate amount of stress to challenge myself' is actually 'I should be slowly killing myself with stress to be a worthwhile person' or 'I'm only challenged enough if it's making me ill' or something similar. Not saying that that necessarily is the case, but I've had issues similar to that in the past, so I figure it's worth mentioning that checking to see if your appropriateness metric is calibrated well.)
