recently on my Deathknight it seems that i have been taking loads of damage that even when i use my CDs that come from a blood spec it seems that i just take much more damage than i should though i can hold the aggro
What kind of content are you doing? Judging by your gear you just picked up this toon after a while away, so if you're doing content that you're undergeared for like ICC that would do it. Also, if it's H HoR then that's normal, everyone gets hit like a truck in there.
One thing about your spec - You need Improved Icy Touch. Having mobs and bosses hit you 6% slower is well worth the talent points. I would lose a few points from either Sudden Doom or Scent of Blood.