Don't waste your time trying to track down a possible hacker. Reclaim control by resetting and changing all of your passwords, and sign up for a password manager (like 1Password, Lastpass, Dashlane, etc.) so this doesn't happen again. At the very first, contact friends, family and co-workers and inform them that you have been hacked. Otherwise they may turn into a victim as well! Then try to reclaim control of your Google account. Check any unauthorized devices at https://myaccount.google.com/ and lock everything down. From there on, reset every password you've got. Make a backup of important data on your phone and reset it. Contact your bank if you think anyone had unauthorized access to your payment details (like credit cards). Contact local law enforcement if you believe other data like your social security number has been compromised. If you are safe again, you might consider contacting law enforcement to file a complaint. They may start an investigation.