This reminds me a bit of the short film "Kid's Story" from The Animatrix. It revolves around a teenager who is waking up to the possibility of the matrix who finds himself alone in a world full of people unaware of its existence. He seeks the help of those who are woken up, specifically, Neo. In a way he is like these children, aware of the fleeting nature of life, waking up to these issues.

I recently had a psilocybin mushroom trip that resulted in a bit of temporary derealization during which I needed one of my friends to hold me just so that I knew I was real. It was one of the most intense experiences of my life, but through it I learned that our existence in this world is entirely a perception of the mind, and that we create our reality through each and every action we take and each thought that we make. Particularly one of my most profound insights was that the concept of time is irrelevant, for there is only the now, and when one is able to perceive the now, then one can be free from the grasps of what if and can one see what is.

I find it difficult to convey these feelings with other people, as I often find them saying things like "yeah, that's interesting", but I can see that they do not truly understand. There are some that do however and for those who do I am grateful. For the children and those of you who find yourself in this "existential depression", I can only offer this...

Create. Create art, create music, create life. If you can leave something behind for the rest of the universe, then your life was not for nothing, for you created something, were a part of something. This at the very least is all that we can do, and that is okay, for even if all you can do is make someone smile, you have created a ripple in the world that will manifest itself as a wave in the lives of those who carry on.