Ouch. Lost 20000 souls today, I really hate sewer levels.
I killed the Capra Demon, and then lost 14000 fighting the giant rat. Then I stupidly fell off the cliffs around Firelink Shrine making my way back.
I cleared out most of Depths, only to get cursed by those mist-breathing amphibian things, and then cursed again trying to get back the 6000 souls I lost.