Sleeping at night

I wouldnt worry about the cancer side of things, however if you're in a place with no light sources and you need to get to sleep (somebody elses house etc.) you should really get used to sleeping in the dark, i'd suggest having your light source with you but blocking your view as much as you can by wearing a blindfold or something like that, eventually you will get used to it and be able to sleep with no light sources, also it is much easier to fall asleep without any light sources, even if you may not be aware of it the light influences how you fall asleep, as a long term sufferer of insomnia i've had to deal with many different issues dealing with sleep including this one.

 

! I used to be just like this when I was younger. I'd be laying in bed when my mind should be most relaxed, but it's complete opposite. I hear every sound and movement.
Maybe you should invest in a lamp that has a dimming option, where each night you could make it less and less intense. Train your body to become used to no light. You'll get there eventually.