You have fallen victim to a potentially unwanted program or other type of malware.
Enter this url into your address bar and delete everything that you don't trust or that looks suspicious, or delete everything.
chrome://extensions
Now follow these steps:
On your computer, open Chrome.
At the top right, click More Settings.
At the bottom, click Show advanced settings.
Under the section "Reset settings,” click Reset settings.
In the box that appears, click Reset.
from: https://support.google.com/chrome/answer/3296214
Finally head to:
chrome://restart/