I'd also like to add that you should never judge yourself by those around you, especially if they are level 19, 29 or 39. A lot of x9 level characters are called "Twinks," which are toons that people have put a lot of time and money into with the sole purpose of being the strongest character in a battleground. These toons have the best gear available to them (often times, pieces that cost them over 100g), and focus completely on PvP survivability, which means high stamina, high armor and above all else, high health.
Having 1300 health at level 40 is quite normal. Having only a few pieces of gear with stamina isn't a bad thing. The closest hunter I have to your hunter is level 27, and she only has 800 health. It's never effected my ability to level because my pet takes all the abuse.
Just make sure to stick with pieces that either have Agility, Attack Power and/or Intellect. Stamina is an added bonus, and Spirit doesn't hurt, but it's the least useful stat to hunters.
And I checked out your armory. Almost every piece of gear you have has strength on it! You need to replace all of it. Strength really doesn't do anything helpful for a hunter at all. Yes, it says that it increases your attack power, but what it's REALLY doing is increasing your MELEE attack power. Agility (and Intellect, if specc'ed properly) increases both your Melee AND Ranged attack power, which is what you want.
So stay away from "of the Bear" pieces. You want to go for "of the Falcon," "of the Monkey," "of Agility," "of Attack Power," or when nothing else is available, "of the wolf"