Sorry to tell you but there's nothing we can do about it. Once it has been transferred there's no way for you to reverse it back. It's your fault, maybe you signed up from airdrop or something. Heads up, if you're going to use MEW make sure that you don't put all your ETH and altcoins in the same wallet.
all my security measures are on
It looks like you have trapped by a phishing site. Have you checked was there someone that can access your PC? Is there a possibility for your PC gets hijacked by malware? It looks like you have been trapped yb fake site.