Well, as others said, show this thread to your DM. He will learn that Rogue is a striker and it is natural for a rogue to be inflicting big damage.
And, while a Drow makes a good Rogue, it does not automatically makes a Uber Rogue. Darkfire may miss. Cloud of Darkness may cause tactical problems from time to time, as it blocks other PCs' line of sight.
Also, making undead or particular kind of monsters immune to sneak attack is really a bad idea. Imagine when you are playing a, say, undead-themed adventure. There are such adventures with good flavor, stories, tricks and prots. But if your DM make undead immune to sneak attack, that adventure will suddenly become just an unreasonable punishment for a player of rogue PC.
I remember the story of a player, who was playing a rogue in 3.0e. He played an undead-themed big-dungeon adventure called "Heart of Nightfang Spire". The dungeon was full of undead monsters, constructs and traps (there were only few living things there). Playing once per month, It took them more than half a year to play that adventure. During that period, he could make almost no sneak attacks at all.