Screen display images enlarged - won't respond properly if at all

Was in the middle of playing a game. Decided to switch to another app game when the screen enlarged as if I sized it larger. All the images became larger. At first I was able to access everything - with great difficulty, but now I cannot. I performed a "restore original settings" and then tried to sync everything back and for a split second the screen was back to normal and then switched back to XL. Not sure what is happening or why the sensitivity. Any clues? BTW I am not tech savvy if you haven't guessed by my description. ;) Many thanks!