At 35 you don't just start doing decent damage, it takes alot of parsing and modifying your spell order to get your damage right. There are four big levels for necro's, 29, 35, 38.6, 45. You just hit the second and the most important in regards to cast timing. Learn your cast and recast timers, they are like a puzzle in regards to maximum damage, interleave everything while your pestilential blast refreshes... figure out everything you can squeeze into the recast timer and you should do pretty well. Necro is all about finesse and the reason is you have to know all of your timers intimately to get your best damage.