Baby is crying and fighting his sleep...

He is sick and does not want to nap. I hold him only to “fall asleep” but he isn’t sleeping, so if I move slightly, he wakes—crying. I’ve given him Motrin and is not running a fever. I am so exhausted. I haven’t slept at night cause he stays up all night due to his comfort so I rock him for the better half of the night. I don’t know what else to do. We’ve been to the doctor, just to rule anything out. But we are still struggling.