The reason you can’t fall asleep until 3 AM might be that you sit in front of a PC/TV till late at night.
All digital devices, as you may know, emit blue light. In general, blue light is not bad light.
Our Sun is, in fact, the main source of blue light – and it doesn’t harm us.
At night you can’t see the blue light from the Sun, because there is no Sun, right? So it’s not normal to look at the “bright Sun” that your monitor is.
When you do it, your brain doesn’t understand that it’s already night and you don’t feel so sleepy even if you are tired.
What can you do about it:
I personally, can’t reduce my time in front of my computer, since I work and study till late at night.
Blue light blocking glasses didn’t help me either, because they only made my headaches worse. Plus they don’t remove the problem – once you take off your glasses the blue light is still there and if you go somewhere and forget the glasses – there’s nothing you can do about it.
So the perfect option for me is a blue light filter.