Sounds like you either need to learn to deal with it, or find another job. 3:1 is not an insane staffing ratio for any ICU, but nonetheless dangerous. Ours is 2:1 no matter what, and if any supervisor tried to make anyone 3:1, we'd have our manager all over them.
If I were in your shoes, I'd be looking elsewhere. You've got a strong resume for an ICU nurse, take it someplace where it's appreciated.