If you don’t want to be here anymore…just…don’t come anymore. Change your password to something you will not remember, which equates to closing the door before throwing the key to the river and then quietly go away.
That and different mailboxes, including two that are used only for less than serious stuff. Using a random password (a random ISBN number or something rare enough (book title, serial number of your latest HDD) for example) makes it rather hard to use your account without your consent.
Word to your mother.