You will need to pick up mining and alchemy. With fort and self buffed my level 20 Alliance shaman runs at over 4,100 health almost 4,400 with food and Halaani whiskey and can easily reach 6,500-6,700 when fully buffed in a BG. And I do not run with stamina rings or AGMs. Stamina stacking is the only way to survive these days.
Speaking of rings. You should try and get both charged gears because of the resistance features. Every little bit of resistance stacking helps.
Good luck!
Sweetsidney