Your gear is lacking.
I have 19.24% dodge and 17.xx% parry, 24.5k health, not crit immune, I'm doing fine.
In fact, I'm going so well, I had 5 saves today, 1 normal, 3 heroics and 1 wintergrasp raid on Archavon.
And I have only 1 epic, the emblem of heroism belt.
each heroic was AoE tanked with minimal CC, Archavon was one-shotted.