Should I take my LO to the ER?

I posted yesterday evening about him having a high fever and projectile vomiting. A dose of Tylenol stopped the committing but his temperature went up and down all night. All throughout the night he spent it whimpering and tossing and turning (different than when he's dreaming). Now that he's awake, I have fed him and got him rest for the day and he still doesn't seem like hisself.. his temperature isn't high but he's still whimpering and keeps crawling a little before he lays down and just stares at me... usually he's very active and all over the place. But he doesn't seem to really want to do much.. should I take him to the doctor or just continue with my day and go to work??