Filatus explained it perfectly.
Helpful hint, Dezza: get more HP.
Seriously, anything to raise your constitution will dramatically increase a character's survival rate, as well as feats like Toughness.
Because creatures hitting you for 50+ damage a pop is not uncommon at epic levels.
(I'm not saying you need to be epic to fight those particular trollocs or that one of those firebombs critting on you isn't heinous, just that more HP really, really does help.)