hit a wall

1. To become completely exhausted, fatigued, or worn out. I hit a wall after only the first mile of the race. I could barely even walk for the rest of it! Isn't he still getting over the flu? No wonder he hit a wall so early in the game. Let's just go home, the kids have clearly hit a wall and are getting cranky.

2. To come up against an obstacle that stops or impedes progress. Our project was going well, but we hit a wall when our funding was suddenly cut. There was no traffic on the highway, but I hit a wall when I took the exit into the city. I know he wants to implement a lot of changes, but I suspect he'll hit a wall when he meets with the board of trustees.