The Fog

One day, you go on a walk in the huge forest behind your house and you decide to go farther than usual. As you walk, fog starts to spill from the trees and emerge from the ground. You become lightheaded, and your head starts to sway, and eventually, you fall to the ground. You gain your composure after a minute, but after you stand back up, you realize something feels off. The trees look fuzzy, and the sky is grey. You're not in your world anymore. You can't tell how far you've gone because you didn't think to bring any compass, map, anything! You open your phone, but...all your apps are gone. All your numbers, pictures, everything is gone! What has happened?