Actually, Ive been having a problem like this for the past two days. Today I shut down AO in disgust.
I play MP..only lvl 8...but Im fighting in a mission...two pets attacking with me...and Im going along fine. Health seems to be good from looking at the bar 47/106, and then all of a sudden BAM Im dead and the health bar immediatly goes right down to zero.
This was happening alot yesterday and a few times today before, like I said, I logged off in disgust. It dident even look like I was getting hit...in that there was no graphical representation that I was being hit at all.