Why is everything lost?

Two years ago my childhood tablet went dead because my charger broke. It has so many photos, videos, notes, stories, everything I did in my childhood was on that tablet. When I finally got a charger, it worked like normal when turning on. However, all of the photos, videos, and everything that was in it is now gone. And whenever I try to change some of the settings, it says I’m having trouble connecting when my WIFI is perfectly fine. Please help.