Everyone gets tired. People remember whether you warned them before you dropped the ball.

Nobody expects you to be inexhaustible, and everyone expects to be told. What people actually hold against you is not the dropped task but the silence before it, because that silence took away their chance to arrange something else. A warning turns your problem into a shared problem with time left to solve it. Tiredness is forgivable, and being left to discover it is harder.

If something is slipping, say so now rather than at the deadline, and say what you can still manage. Name the specific thing you will not get to. Do it even while hoping it might work out, since an unneeded warning costs nothing.