Inconsistant sleeping time

Yesterday slept at 5am,huh,studied programming and did the tutorial then i arranged some of the files,after tat still cannot sleep,sometimes when u`ll feel very tired but just then u cannot fall asleep,tats the worst feel ever,since tat u`re tired and cannot concentrate to do anything,u have to sleep ,but u can`t sleep,what on earth u should do???Hmm...only can wait till u fall asleep....today even worse,unfortunenately ate something wrong and got stomachache when I was very tired as lack of sleeping.Then at night watch webcast halfway then feel sleepy,so i decided to sleep 1st and then wake up at 3am.But then sleep tilll now i`m awake liao,naturally,not by alarm,i oso dunno y...perhaps my body want me to work hard.....