[candu]

Well, you can always leave.

Usually this should start with a frank conversation with your manager. Something like this: "For a while now, I've been fielding IT requests from the entire company. I appreciate that you've been helping manage expectations upwards, but my workload is still unsustainable, and to be honest I haven't been enjoying my work for a while now. If this situation doesn't improve by {insert near-future date}, I'll have to leave."

And then: just start saying no to things. Someone high up says "I need X immediately"? Either say "well, I'll put it on my backlog, and I can get to that in Y weeks" or "I can do that immediately, if you go to these people and tell them I can't do what they asked because this is higher priority."

At least, that's if you want to do it the gradual and non-bridge-burning way. You can also decide that game isn't worth it; there's lot of other tech jobs out there.