I can relate to this. I used to be on call for many years and honestly, it destroyed my mental health. In the last company I did it, it felt like falling in a meat grinder for a week. I remember once spending a whole weekend giving support on an bug that was introduced by a recent release. 72 hours of working non stop. Because of that among others, I got a severe burnt out that took me to the deepest dark place I've ever been.

To this day, I simply refuse to do on call. There's no enough money you can pay me that would make me to suffer that again.

PS: Fuck you, Rackspace.