We own you
medium.com
medium.com
"I'll have to check with _my_ lawyer before I sign this".
I'm fairly sure that 'my' lawyer does not consider herself to be one of my personal possessions.
This is just normal English, not necessarily an assumption of total ownership.
I agree with everything else though: don't work yourself to death for a company that knows no loyalty. Do what you're paid to do, but they don't own your soul. If they want it, they should pay a lot more.