Welcome to the world of being a Wizard. Simplest solution is to get Bulls Endurance, cast it, and have +8hp when in a bad spot. *shrug*welby said:My current wizard (necromancy) has no con bonus, and as such I have 12 hit points at level 4. And if that's not bad enough, my AC is 12 (mage armor is in an opposed school). I'm feeling like anything that wanted to kill me, could, and it's just by the DM's mercy that I am alive. But I'm bound to get caught in some area effect spell or trap eventually. Long story short, I'm feeling pretty frail.
Featwise, Improved Toughness (Complete Warrior) is +1hp/level. You WOULD have been well advised to take Mind over Body (use Intelligence modifier instead of Constitution modifier at 1st level, and gain +1hp for each metamagic feat you learn), but that can only be taken at 1st level (issues of Region aside).