Insomnia? cancer? hard time sleeping at night. stay up till 3-4 am and sleep until 3-4pm. sometimes tired during the day but not much? what is this?

Insomnia: Set aside a quiet hour before bedtime. Turn off all electrical appliances including the tv. Listen to some soft music. Read a boring novel. Take a warm bath . Go to bed at the same time every night.

Can't sleep: Talk to your doctor about this & see if you need assessed for secondary insomnia (insomnia due to other organic or psychological factors) which can be treated. Meanwhile you can try the sleep hygiene techniques.