Fixing Accidental Parental Controls on YOURSELF
If you're managing parental controls for children, you might accidentally put them on yourself if you don't realise you've gone into the wrong 'Content & Privacy Restrictions' window (they look the same for your own, as they look for your children). I accidentally did this, restricting ALL APPS and ALL CONTENT! Of course, then all my apps disappeared and so many of my life-functions were inhibited. Opps. I couldn't find a quick fix online and some advised starting a new administrator account and trying to reset it all.
However, what did work was going to the settings 'search' and searching for 'restrictions', which took me straight to the page I could no longer find, and I could turn them all back from there. Try this as it saved me a LOT of problems.