An attempt to login to my Google account

Greetings,
Recently I've had quite a worrying thing happen to me. I've recieved an email that someone with IP adress of 184.3.227.83 (quick search asured me that it's an American proxy) tried to login to my gmail, but got blocked as it's unknown device.
That would all be okay (I know all about safety on the internet), but there is one thing that caught my eye.
I've created this Google account SPECIFICALY for registration on Warmane, and don't use it anywhere else. I use different passwords everywhere, and I've tried to search for my password in all password wordlists (including the darknet ones) I could obtain. No match.
Getting to the point: I think it's Warmane that does not use enough security measurements in order to block bruteforce attacks (Google does, so I think there is no possibility that the attack would not be related to Warmane).
I've heard from friends that their Warmane accounts were hacked as well before, but thought nothing of it, as it's usualy user fault.
I've ofcourse since changed the password on both Warmane and email, checked my characters and found nothing missing, but the whole thing is worrying.