Haven't got a clue
/When you haven't got a clue, what do you do? Hadn't meant for that to rhyme. But now that I have made a rhyme, perhaps that is part of the answer.
Write a poem.
Make a song.
Doodle.
Using these gentle techniques, I often find a workaround or enough of an answer to continue and it's much less painful that beating myself up for solutions.