Map crashed while inside and caused a rollback.

I was clearing a t16 8mod Core map. Activated a legion pylon and once the monsters became active few seconds later my game froze and game crashed. Once i logged back in my inventory was totally empty, everything in my inventory was gone. The Portals to the instance disappeared once i clicked on one of them and a text of "Cannot connect to instance. That subarea no longer exists" Skills i use is ball of lightning, herald of agony and 4 spectres called "Stoneskin Flayers".