Warriors are a little bit lower on health than their DK and Bear counterparts. Don't sweat this. If you have CTC you'll be fine.
Think of it this way.... with CTC, you never take a "full" hit. You don't have to have as much health as you aren't receiving as much damage up front.
DK and Druid don't have CTC. Everything they have works a bit after-the-fact. They "have" to have more health for their classes to function properly.
Even then, consider.... once you start getting some tank drops FROM DS, you'll start seeing your health climb up. The stat increases you will see from new gear pieces will outstrip anything you can do with gems anyway.
So, don't sweat it too much. Just aim for CTC..... don't be afraid to use cooldowns/trinks to keep things as comfortable as you can.
No one tanks in a void.........