Yesterday I was researching something and didn't notice that McAfee hadn't put a green checkmark beside it but it had a ? instead. I clicked and immediately got a huge square with ATTACK SITE! in the middle of it and then it came up something with porn so I immediately closed the Fireofx tab and then Firefox itself.

Question-- any opinions as to what happened and what I should do? I have complete McAfee and it's constantly updated.

I'll be more careful in future to make sure that little green checkmark is there! I'm scared some friggin' malware could have been inserted or heavens knows what else.