J.Y.
My youngest has terrible reactions to vaccines, even though I only let him get one at a time. Last time, his symptoms lasted about 10 days before he seemed mostly himself again. Does you son sleep better after the Tylenol? He could possibly be in pain. There are a myriad of reactions to vaccines that could be bothering him that he can't explain. Crying is the only way he can tell you something is wrong. Maybe try Motrin as that lasts longer. Have you considered cosleeping for a period of time until he gets to feeling better? You may both get better rest that way. I hope he feels better soon.
Also, my children go to bed around 6:15-6:30pm every night and sleep until 7:15-8:00am. My 21 month old always wakes frequently throughout the night if he goes to bed any later. I doubt an early bedtime is the problem.