'Hack tool detected'?

So I logged on today to play, but before I even played a game, the message in the title came up. I have never used hacks at all, so I have no idea what's going on. I have screens of it but I don't know how to post them. Sometimes when I try to login, it says I'm already logged in. Does this mean I've been hacked or what? I'm really confused and scared that I may lose my account. Sorry if this is in the wrong section, I just need help.

Thanks