59% dodge/parry/block - 41% of hits are coming in unmitigated. You are getting hit hard.
One of your rings, Shoulders, gloves, and pants give you zero surviability.
You have way to much hit/exp and no reforging/enchanting and your gemming is not right.
But it is all fixable.
A) Shoulders, gloves, and pants - replace the PVP gear with nearly anything else. You'll lose some HP and a small bit of armor, but really the difference in armor is minimal in effect. And the stamina is just a bigger HP pool that needs to be healed up.
Yellow = 40 mastery
Prismatic = 40 mastery
DPS bonus (hit/crit/haste/etc) = 40 Mastery
Blue = 20 mastery / 30 stam
Red = 20 mastery / 20 parry
C) Enchants - If you're serious about tanking then there is no excuse for not enchanting item level 346 gear with sub-maelstorm enchants. And even 333 gear because the enchants are relatively cheap for the 2nd tier.
D) You have ten pieces of gear with no mastery on them. Every piece of gear needs to have mastery at your item level.
D1) Reforge to mastery first, if the gear has mastery reforge to parry.
D2) Reforge away from crit first, haste second, hit 3rd, expertise 4th, dodge 5th, and parry 6th. Meaning if you're choosing between expertise and dodge for example, reforge the expertise to mastery first.
E) Your spec is needs work up.
Okay, I could keep going, but you're looking like you're going to for CTA tanking? I know it's a big read, but tanking is a big job, read the primer in my signature (it's not perfect, I have mistakes in there others have caught below) and re-gem, reforge, and regear what you can. At that point you should be in pretty good shape.
If you have questions after reading about rotation, placement, cooldown usage, etc.
People can offer suggestions in addition to what I've posted, but in reality, you need to research a lot more so you understand why we're making these suggestions. I know learning to tank is hard - I still remember being fail tank being carried by the great pally MTs I ran with - but that's what we're here for. Read the primer, and then ask specific questions and we'll get you squared away
Now lets retrofit you into a proper WarTank