The cure is to go back to the drawing board and figure out where you screwed the story up. The way forward could be as simple as introducing another character or as difficult as re-outlining the current story arc.
My screenwriting goes in spurts. 7-10 pages a day for a few days, then rest for a day or two, maybe a week. I hit a wall in the screenplay I was basing on Enron + Robin Hood. Just around the Act I to Act II turn.
After two weeks, I got a print out of the last 10 pages, a pen and some highlighters for color coding, and figure out what was wrong. A couple sections in the wrong places. A dangling paragraph or thought. One afternoon, about 2 hours, and then it all felt right again. Went back to the routine and got it wrapped up.
that GRRM doesn't really like his options from where he is in the story
If anything, most pop/rock musicians do their best work on their first records, when there's not any audience yet. It's the rarer beasts, like Beatles, etc that improve with later releases (this doesn't usually apply to jazz and classical, where maturity and experience matters more).
Besides, the idea of an artists having a writer's block because they have to follow a large hit, or feel pressured by their huge audience and the demands that entails, is so common it's almost a cliche.
Its interesting to note that a lot of people parallel The Beatles with U2. U2 was always ahead of the curve in terms of music they were making. They were using EDM in their music as early as 1993 - years before other bands even began experimenting with it. Their Zooropa album had themes of electronic over stimulation and it was the start of them breaking away from their traditional sound - something they would continue doing until 2000's All That You Can't Leave Behind.
It depends on the artist, IMO. Some people are charged up by a large consumer base waiting for more work, some don't care, and some are frozen by it.
Best if you don't care -- per HR's discussion of Miles Davis. Sometimes Miles left his audience behind, but that was OK because he was being true to himself and his vision for his work.
All new writers\performers\creatives have 0 people waiting to receive their work.
You don't need motivation, you need discipline. Write\create\whatever. It will be the only way to turn your 10 readers into 10,000 readers.