If you can't keep a sorceress from getting killed you might have problem with later encounters. You might want to try learning how to use your survival-spells accordingly instead of rerolling.
One of the most fundamental defensive combination of lowlevel spells is Mirror Image
which will make physical attackers much less likely to gain anything from targeting you. In many situations, Invisibility
can also be a life-saver. All of these are level 4 or less and available from scratch.
Once you reach higher levels you gain availability to some of the best defensive spells in-game, namely Protection from Magical Weapons
, Protection from Energy
and Spell Immunity
. When adding these to the basic setup I just described, you become way harder to take down than any warrior/rogue/priest out there.
And that's way before you get Time Trap
, Absolute Immunity
and the like.