I hope your insomnia has been over by now. But here are something that could defile a good night's sleep.
- exercise in the evening or at night (Exercise helps some people to sleep. But in some, it raises certain hormone levels and could keep you active for hours.)
- computer and TV. They are too good stimuli.
- your air-con noises, water dripping, street lights, etc.
Anyway, if you think it's because of your work, you might wanna try listing down the things you have to finish and the time you need to work on them. This works for me as after I do this I always feel that I still have enough time (and leave them til later

)
Exercising a bit (during the day) could help a great deal too. It's a cure for everything.
