It does sound like you changed your resolution. Right click on an open area of your desktop and choose properties. The display properties window will open and go to settings section and choose the resolution you want. Choose a higher resolution and click apply and wait.If right click does not work try going to control panel in your start menu and choose display properties, the same window mentioned will open and go to settings.How do I reset the resolution to factory settings on my computer?
What it probably was is something with the fn key.... so look for something that is the same color as the FN somewhere by the numbers or fnumbers and possibly fonts.. hold fn and hit that button... or 2.. you held down the control key and scrolled with your mouse...
So try that hold control and hit the scroll on your mouse, if not try the fn font
if you dont have an external mouse with your laptop idk if its possible to do the crtl and scroll... so its probably Fn then font