How do I change my app icons back to normal?

Locate Apps or Application Manager (depending upon which device you use). Swipe the screen to the left to get to the All tab. Scroll down until you locate the currently running home screen. Scroll down until you see the Clear Defaults button (Figure A).

How do I get my original icons back?

@starla: You should be able to revert to the default icons by going to Settings > Wallpapers and Themes > Icons (at the bottom of the screen) > My Icons > View All > Default.