Canceling to stay in and recharge doesn’t make you a bad friend. Showing up empty might.

Being a good friend is not the same as being constantly available, and there is a version of showing up that gives nobody anything. When you arrive already emptied out, you are present in body and absent in every way that counts, and both of you can feel it. An honest absence is easier to work with than hollow attendance.

If you need to pull out of something, say so early and plainly rather than at the door. Offer a different time if you want one. Then spend the recovered evening actually recovering, since the cancellation only pays off if the rest is real.