I know what you mean...HUGE ICONS! My son suggested I turn it off and then restart the phone. This does work, however sometimes I have to touch it again and again just to get the little slider into view, so that I can turn it off. I don't know what sets this off, but it's most inconvenient.
Another solution that also works, though irritating, is to remove the battery and put it back in. GOOD LUCK! I'm with you!