It sounds like a rotation problem. Above that there are glaring spec, and enchanting problems.
You've only killed 2 raid bosses in this tier, so I'm wondering if you have threat problems in 5mans? Where 90% of your threat problems are caused by dps attacking the wrong target, but if you would post your rotation. I established the system of "If you die to getting aggro I don't rez you". This teaches dps to watch and/or install omen.
[Today 06:48 PM] Ion:swimming in a natural body of water ISN'T acceptable...it's momentarily tolerable