We have added a email account to your 'teacher@ghcdsstudent.org' account and it wants you to log in using 'teacher@ghcds.org' instead.
If you are trying to log into google and it won't let you, click on 'Use other Account' and log in as 'user@ghcds.org' instead of 'user@ghcdsstudent.org'
Example: lyoder@ghcdsstudent.org is now lyoder@ghcds.org
Next, use your same google password as you had before and you will get in to your account just as before.
The attached video will help you.