Improving Avoidence, Falling Health Pool (DK Tank)

[Mardoran]

Hey all,
With the new patch, and the ease of upgrades for myself (read 232 gear) i've been upgrading my gear.
The issue i am currently grappling with is my falling health pool. while my avoidance continues to stack my amount of health keeps falling.
Let me know if i should be concerned, along with suggestions for re-gem/chant.
With what is currently on the armory (two high sta trinkets) i'm stting at a health pool of 34.1k, with the two trinkets listed below i drop to a very unimpressive 30.5k
Armory:
The World of Warcraft Armory (http://www.wowarmory.com/character-sheet.xml?r=Khadgar&n=Mardoran)

I also have
Purified Onyxia Blood Talisman - Item - World of Warcraft (http://www.wowhead.com/?item=49487)
and
Ick's Rotting Thumb - Item - World of Warcraft (http://www.wowhead.com/?item=50235)

[Harmacy]

You're under the defense minimum (535 for heroics, and 540 for raids) and as a result are likely being crit to death. Get Stoneskin Gargoyle on that weapon immediately.

Keep the stamina trinkets, and I'd suggest gemming more stamina instead of threat stats. If you find yourself struggling for threat, speccing into Bladed Armor and 2h specialization will fix that problem for you.

[Mardoran]

the def cap thing was an awkwardly timed armory update after picking up my t9 gloves.
as for the respec i'll definatly look into that and trade off to sta gems
the issue wasn't with threatgen or staying alive, its just my health pool has been constantly falling as i acquire higher level gear