Puzzling

I wonder whether other SASSIES suffer from the same problem I'm regularly confronted with?

I have an idea for a story. I start to write and the ideas flow. I'm enjoying myself. But when I reach - roughly - the halfway point, the ideas that got me going just... dry up. I sit there, trying to think of ways to proceed and everything I come up with feels wrong. I might even write it. But it keeps feeling wrong. 

And I know it.

What started out as fun becomes anything but.

I haven't found a solution yet.