Here are several alternative ways to say "I'm up against a wall" depending on the context and tone:
I'm stuck.
I'm in a tough spot.
I'm in a bind.
I've hit a roadblock.
I'm at a standstill.
I'm cornered.
I'm facing a challenge.
I'm out of options.
I'm in a pinch.
I feel trapped.
If you’d like alternatives for a specific context, let me know! 😊