49 here, I'm not enjoying working in IT nowadays, I think it got old about 5 or 6 years ago. So I quit and I'm pursuing my own projects, doing some programming, and trying not to worry too much. I could have ground it out for a few months more in that lucrative contract I had, but just how long can I put up with being
that bored?
Personally, if I have to go back to the circus, I'll probably aim for short contracts or part-time work. If you're looking to reskill, I see plenty of sys admin jobs out there. Except you're supposed to call them "Dev Ops" nowadays. Puppet, VMs, Vagrant, Ansible, cloud computing (Linode, Amazon, etc). It's a relatively small domain which is applicable to many different areas of IT, so you get that "good old days" thing where a little effort goes a long way.
Good luck with whatever you do. Don't let the demons of despair take you, make a deliberate effort to be optimistic and cheerful. You're not the only old horse out there wondering when it all became so complicated. OTOH, it's truly an incredible time to be alive, so much stuff going on!