Your OM should’ve put it in MyTime, HR just puts it in payroll, they don’t approve/deny anything.
If you want to err on the side of caution, call and talk to an OM in your dept to be sure you’re off.
If your dept is on mandatory this week then they shouldn’t have approved Saturday, once the mandatory call is made the calendar is supposed to be locked and the call should’ve been made before that. That’s not to say some won’t still do it, but they’re not supposed to.