Why is DRK so squishy and how do I stop it?

[Awful]

DRK are the most fragile of tanks in nearly all situations except against magic. Most DRKs I've seen are wearing armor made of papier mache. It's not your fault, DRK is just that weak.

You've probably seen Drks that don't pop CDs and literally sit there getting gang beat by everything in plain sight i've been helping my friend lvl a bit who's new to the game they don't play that much but I did almost all their dungeons with them if not all I found that:

-When I tanked Brayflox - Qarn it was so easy to keep up/chain pulling. Ran it as Drk the first time, War 2nd time no difference, same pace. Did it as a pld was awful (don't get shield oath till 40...why SE WHY!) so dmg coming in was more noticable

-Stone Vigil- Dzmeal. I found SV hit harder than DD the difference was astonishing and the mobs in SV can drain a bad tank who's not popping CDs. Found it easier as a Pld surprisingly. DD was faster/easier than Pld though on War and Drk due to more DPS/AoE, however Pld was bulkier due to getting Sentinel and Bulwark etc.

- Cutters Cry. Easy on all the tanks nothing hurts at all,I also had shield oath due to paladin being 40+, nothing really stood out to be honest.

- Aurum Vale. Ah yes ol AV did it once as a Pld and the 2nd time as a Drk, 3rd time as War, chain pulled/CDs the whole shebang didn't take hardly any dmg with my Sch friend. Found it easier on Drk and able to drop Grit in more situations then using Sword Oath on pld and more threat on Drk and drk has more AoE dmg compared to Pld which made it faster. War was easy Vengeance + Bloodbath + Steel Cyclone = GG.

Like I said I am ilvl sync'd but it really shouldn't matter unless a tank has a REALLY bad weapon/armor/accessories you'll only notice a squishy tank and add it with a tank with no CDs you're in for a terrible terrible time. I also found Paladin suffered the most out of all the tanks as it felt I dunno sluggish? That's my general feeling about Paladin I just prefer to run as either a Drk or War it's a lot more enjoyable and out of all those dungeons Pld took less dmg in SV and that's about it the other tanks out preformed it.

Edit: Forgot to add in Cutter's Cry d'oh.