i think this happens because the brain only registers the passage of time when were not hyperfocused or distracted and because of adhd were nearly always hyperfocused or distracted unlike neurotypical people we have to force our brains to come back to reality every once in a while otherwise you are training your brain to think that 1 hour and 4 hours are exactly the same amount of time because when youre distracted or hyperfocused they are   a useful trick can be to just sit around and do nothing every once in a while literally nothing try not to even get lost in thought stay present in the room for like 20 minutes and suddenly 20 minutes will seem like an eternity