High Contrast issues in Ubuntu

I recently got a new computer and installed Linux Ubuntu. I was messing around with the settings. I clicked the Accessibility icon on the top, and clicked High Contrast. everything got bigger, and the background became gray. I can't seem to figure out how to disable it. When I click High Contrast in the settings, it makes the windows black and white. Clicking the same button that I clicked previously has no effect. This is my first time with Linux in general, so please be detailed. (I have the latest version of Ubuntu as of May 25, 2016)