Switching classes

Well dang, maybe I’m just not playing it that well. What are your rotations like? I throw on Three Dots and then start hitting with the single Target or AOE spells depending on how many I pulled. But when I have let’s say three to five trash mobs on my guy I notice the damage just doesn’t seem to be there and they start hitting me pretty hard. Hard enough I have to stop and heal while the dots finish them off. I’m like what gives, these are trash mobs and on a warlock I steam roll through them. And I’m in leather, and the lock is in cloth.