It feels impossible to get your butt off the ground, but when you push your hips into the wall, you get tension on both legs and stand very securely in the position to reach further.
Rain sucks, but broken holds suck even more. Remember, never climb on wet rock in Fontainebleau.
The sandstone becomes brittle, and pulling on it will ruin classic problems. Drying it doesn't help, because it's still wet and weak inside.
All you can do is wait for better conditions.