Usually when you're taking a lot of damage, it's because of poor cooldown usage. That being said, there's some stuff I can recommend:
- Eternal Glory is a weak talent for Prot now that WoG has a 20 second cooldown. Put those points in Judgements of the Just, which makes your Judgement target attack 20% slower (which is a crucial debuff for survival).
- This doesn't really relate to your survivability, but Hallowed Ground is one of your worst threat talents. I'd spec like this personally: http://www.wowhead.com/talent#sZGMhcRkdRRucbG, obviously there is room to play around with some of the optional talents but it hits all the core stuff. It's also worth noting that the Consecrate glyph doesn't help you get more ticks, so it's pretty much useless.
- Level up those professions!
- Stack more Mastery. 42% block is, no offense, really REALLY low even for a 5-man tank. You should be reforging everything to Mastery. (Some people will tell you that hit and expertise are useless - they typically are for raiding, but it's okay to seek out a little bit for 5-mans because you can't rely on a full Vengeance stack or misdirects for initial threat. Just don't go overboard)
- Heart of Thunder is a pretty weak trinket, I'd work on TB rep for the Mastery/Resist trinket, which is amazing.
The way I go about reforging is if it has a avoidance stat and a threat stat, reforge the threat stat into mastery. If it's got two avoidance stats, reforge the higher of the two to mastery. If it's got avoidance and mastery, leave it alone.
Your neck, I would reforge that expertise into dodge. Your back, I would reforge the hit into mastery. Your ring (Talonguard) I would actually reforge the parry since it's probably the higher of the two into mastery since you get more from mastery and just live with the expertise.
For enchants, I would put +50 mastery or greater mastery on your gloves. The twilight leg armor does no good for plate tanks no more with the agility change, so get the drakehide leg armor for stam/dodge. Put dodge on your bracers.
For gems, lose the stam gems. I would go pure mastery unless you need the socket bonus. Maybe mastery/stam to match the socket bonuses if you really want to. But pure mastery gems in yellow sockets and prismatic sockets.