Usually lately when I use whirlwind attack I become bugged, and am unable to do any other attacks without relogging.

This is a bioware bug I believe. Try switching weapons, sometimes it clears it.

I'd like to add that Whirlwind attack did not give full AB against any monster but the first. After the first it gave -6 AB, so that when my test character would attack five rats, the last would be attacked with a -23 AB.