Raise your baseline until average days still move you forward.

If your average day produces nothing, you are relying on rare good days to make any progress at all, and there are not enough of them. Raising the baseline so that even a mediocre day moves things slightly forward changes the arithmetic entirely, since most days are mediocre and they now count.

Define a small amount of real progress that you could achieve on an average day and make that the minimum. It should be low enough to survive tiredness. Once ordinary days contribute, the total over a year stops depending on inspiration.