My character didn't die in Campaign

Heroic_Defender

So I was playing in Campaign: Scourge and a few other EP including me where about to flank some AD, then as we attack my characters health hits 0.0% and doesn't die, but then I try attacking AD and I couldn't attack or use any of my abilities and my health began to regenerate, so I moved to the other side away from combat behind a rock. Which I was very confused as to what was happening, so I quit the game and reload the game, next as I am loading in with my character. I was dead behind the same rock when I moved away from combat. What just happened?

GiuEliN0

Lag, i think just this