I believe he is doing it through my email through Google
If someone is 'hacking' your phone keep in mind most sophisticated spyware tends to be hard to detect and often hard to remove. If your stalker isn't all that tech savvy though the odds are he might only be doing things like harassing you through the typical social networking services. In that case be sure to change your password on those services. For something like your Google account, try logging into your email using a web browser and in the bottom right corner there's a small link titled 'Details'. Click on it an window will pop up showing what logins are active with your account -- type of access, general location by IP address, and date/time. You should see the past few hours of access, typically if you use a computer, a tablet, your phone they'll be in the list but if you see anything out of sorts, say some strange location, there's a 'Sign out all other web sessions' button at the top. Hit the button and be sure to change your password, that way if for instance your stalker has some old device that still has your account set up to autologin it won't be able to any more.
Hope you get this all sorted out. Good Luck!