Help with sleep and sickness

Samantha
Hey guys I hope someone can help me 
It might sound ridiculous but whenever I go on holiday with a time difference when I get home I'm always sick because of the jet lag. 
I recently went to Vegas it was an 8hr time difference it's been almost a week now and I'm still not sleeping I manage a few hrs everynight finally sleeping at about 5am. And as a result I'm really sick the next day. 
It's not morning sickness either. 
I struggle to do anything it's really bringing me down 
Is there anything that can help me sleep at night. I'm just laying there for hoooooouuuuurs. I wouldn't say I'm stressed or have a lot on my mind so I think it's just my body clock not adjusting.
Please help
Thanks in advance 
Sam