I don't know what - When you're stuck on a math problem so hard, you're ready to

When you're stuck on a math problem so hard, you're ready to cry, and you just say this like it's a spell to make it go away.

I don't know what. This math problem is eating my brain.

I don't know what. Why is calculus my enemy?

I don't know what. I just want to pass this class.