Well.... you knew what you were getting into... so... why?
On a serious note, man, that does suck. I think a few players have been tempted to re-run the Sewers thinking some random loot chest would offer up a nice reward only to find out there's just more death.
Re-running the sewers can be a good source of XP, or a way to finish off any named beasts you let live on the first way through, but unless you've already finished all the content, there's better things to hit head against
It is only 1-st time like hell, next time you should come there more well-fit.
P.S. SoH is easy for mages if you have mage barrier maxed and enough body development with fire resistance, i even do not take any poison potions there, it is only run.
at what level did you do it? because at level 25 it was very hard for me. i had to use many potions ans scrolls...i had all the defense, except mage barrier at level 2 only...you can not get all the spells... i was used to have it maxed, but when i had to face the lord carrion i decided to max desintegrate instead...i had to erase all my advanced skills, this costed my more than 50k...
this game is very hard for mages...when facing magic resistant monsters...