Insomnia???

Jamielee
Been suffering insomnia as long as i can remember but recently its got a lot worse. Can hardly sleep even though im up at 7am everyday, working until 6pm, i have a healthy diet, coffee in the morning and occasionally lunch time, i eat lunch and then dinner once im home from work and never eat past 9pm usually. I drink 2 litres of water a day aswell if not more.
Any tips or ideas what it could be caused by? 
I thought it could maybe be the hormones cause by depo provera but its worn off and has been for 3 weeks with no improvement.
Help!!