How do I know if my sleeplessness is Insomnia

I think any time you really can't sleep it's called insomnia. It's a fancy word for inability to fall asleep or stay asleep. It doesn't mean you necessarily have some kind of disease. Insomnia can be caused by a whole bunch of things. Check what you are eating in the evenings and your overall nutrition, caffeine and poor nutrition can be factors, particularly caffeine. Also, it could be stress/anxiety from something going on. If you feel stressed in any way or there is any one particular thing on your mind, try to write down what it is and any possible solution that you are thinking about. That way you won't have to worry about forgetting whatever it was that you were thinking about. That helps me a lot because sometimes things pop into my head when I'm in bed that I think "oh, I have to remember that" and I just leave a notepad on the nightstand with a pen and scribble down what it was, hard to read since I do it by feel, but that way I know I can stop remembering and just go to sleep. Another thing I recently heard is that looking at a screen either computer or TV is a high stimulous because it is made of light. That means part of your brain, though not necessarily all of it, is very awake and active. You mention you are on the computer at 4:30 in the morning. You may be one of those people whose brain need to unwind a little more slowly. Try staying away from computer and TV or a while before bed, dim the lights as well and see if that helps. Not everyone is wired such that they can go from very on to off instantly