"How do I fix this problem with my MacBook? Big letters, big icons, big EVERYTHING!

If it has a multi touch mouse pad tap it then pinch together on it.

Sounds like a resolution setting…

Click on Apple Logo in top left corner.
Click on System Preferences.
Under Hardware category – click on Displays.
Change the resolution to the highest it can go.

Hopefully that can fix the problem.

@rpmpseudonym I didn’t worked, LOL..

Try Ctrl + 0.

Okay, now I’m starting to panic…

Is the full desktop visible? I’m trying to establish if this is a resolution/display setting or a zoomed in feature or the magnifying glass feature.

If you move your mouse around… does the screen shift around with it?

What if you right click not the desktop, choose -Show View Options, then slide the bar on grid size & icon size & see if that manually changes the icon resolution.

Control and the minus sign should bring down the size of items inside your windows. Apple – Dock – Preferences might help with some things, too.