Why does everyone above and below me think I'm failing them?

Here is the plain truth. You stand between two groups who each want something the other side won't allow. Management wants numbers. Your crew wants protection from impossible demands. Both blame you when they don't get it. This is not a sign you're failing — it's the shape of the job you took. You didn't sign up to be loved by both sides. You signed up to make sound calls with limited resources under pressure. Nobody warned you that doing this job well still means someone walks away unhappy, often daily. That's not a flaw in you. That's the actual work. So stop auditing yourself by whether people are pleased. Start auditing yourself by whether your last ten decisions were honest and reasoned given what you knew. That's the only fair measure. Everything else is noise you don't control.