Help...baby doest sleep at all!?

everyday is different, but still the same amount of sleep, today- went to sleep at 12am got up at 3am was up till 4:30am slept untill 8am then was up for the entire day, maybe 20 mins of naps at the most. he is so tired i can tell. i tried the sleep time bath, he has a full belly, clean bum. i dont know what to do i am soooo tired. help me please