Check and do the following...
First, please browse to chrome://extensions and turn off any that can be turned off, especially if they don't sound educational.

Second, remove your user profile from your Chromebook and re-add your profile account to see if that clears up any issues (see steps below). 

Step 1) Please log out of your Chromebook
Step 2) Please remove your user account on the Chromebook (presume you don't have any files in the Files app you won't mind losing -- if you do, make a backup of them first)
  1. On the Chromebook sign-in screen, select the profile you want to remove.
  2. Next to the profile name, select the Down arrow .
  3. Select Remove this user.
  4. In the box that appears, select Remove this user.
For a video tutorial with these directions, please visit the link below.

Please restart your Chromebook.
Please log in again (add yourself back as a user).