I don't immediately realize when I overexert myself. My natural is to zone in on one type of activity for hours. Until I'm way exhausted.
Fatigue has an emotional component. Dividing my day into pockets of work, adulting, exercise and relaxing helps me balance my energy levels.
I find it much easier to keep my energy pockets small with external help. Usually by having plans that limit how much time I can spend on one task.
Sometimes plans really means playing with cats. Crunchy is really good at demanding I make time for him as promised 😸 #catsofmastodon