Losing Capacity

I suppose that one can lose their capacity, or at least their motivation, at any time to do anything that they believe required of them, simply for the reason that they run out of steam?! And it seems that is only when one really takes stock of their surrounding and happenings that this very happening or none happening one should say, is brought to the fore. Today I have run out of steam - well of course it is Sunday and I bear not to think of what will come Monday but indeed Tuesday seems much rosier.