3 year old won't sleep

[5minutestobed]

DS gas never been a good sleeper although he has improved a lot since he was a baby. He has recently decided though that he doesn't like sleeping and doesn't want to close his eyes. Which results in him staying awake for hours at bedtime or during the night or waking up at 5am and refusing to go back to sleep. Then he screams and cry's because his eyes hurt...
What am I supposed to do?! I am 8 months pregnant and fed up of spending half the night sitting on his floor telling him to lie down and go to sleep.
Anyone had similar issues, what did you do?

Bump

Is he old enough for the 'you don't have to sleep but you need to lay down with your eyes shut' trick?

No he just screams "not shutting eyes!!!!" At me if I try that!

Bumping!

Ok it's time for tough love. He must be shattered, and you are going to be on your knees when the baby comes if this continues.
He is old enough to understand that bedtime is for sleeping and you are not going to be entertaining him at all hours.
Go in, tell him it's time for sleep and that you are going to bed yourself. Then leave him to it. He will yell his head off for a while then conk out is my bet. Reassure him that you will see him in the morning and that you're just in the next room. It's more unkind in my opinion to let him maintain this bad habit as he must be exhausted and cranky all day no?