i’m doing the best that I can, and that’s all I can ask of myself.

Your best is not a fixed quantity, which is where this usually goes wrong. On four hours' sleep, in the third month of something, after a difficult phone call, it is a smaller number than it was in a good year — and it is still your best, being fully spent.

The comparison people make is always against their strongest week. That's a bit like a runner judging every race against the one run with a tailwind. Today has the conditions it has. What's being asked of you is everything available today, not everything that was available in March.