My Account got Hacked HELP

Hi everyone heres the issue i am facing now , just 30 mins ago when i try to log in my niche insta account it give me an error of " password incorrect" i never changed my password before and i log in to the email i created and guess what , that email was hacked too and now i cant access both my gmail and insta account . Can someone help me please? this account is very important to me . BTW i got an idea who did this (refer to the image below) As i standardized my password for my niche accounts i was shocked to find out he managed to access 3 of my gmail account each link with a different niche Instagram account. Is there way to recover my gmail OR more importantly my Insta account? I am really frustrated right now. And how to prevent it again?

Gmail privacy is the best. You can ask for a password change, go to recovery options. Gmail will ask you for account characteristics, including details of your last sign up, and emails. This should help if you remember that information.
For future you can go to privacy settings and prevent log in from new browsers till code verification.