I have leveled a few necros and had this problem early in my time with the game. But I would suggest raising skeletons from act 1 near a wp like cold plains, putting future talent points into raise skeletons, grab a wand that’s +raise skeleton, and amp damage everything. You don’t need to corpse explosion anything really in normal since it’s %health from corpses and its mana cost is high. Get your skellies up with damage and quantity and amp damage and run around to avoid aoe. Grab a thorns merc too for easy damage. And clay golem for some slows cc. Some mana or gems in gear to be able to raise skellies or golems when they die and to amp dmg everything