Logically, there is no purpose for our existence. The idea of "Humanity" is merely a construct shaped to preserve our species, which, like all life, are mere biological automata. Our emotions our simply chemicals. There isn't anything different or outstanding about them. Our intellect drives us to seek meaning, find truth, justify our existence... But it's hopeless. The universe, as we may all someday discover, wasn't made for us or other emotional, sentient beings. The universe is dark, cold and inconceivably vast. Happiness is, logically, irrelevant. If you consider the implications of this and other aspects of our existence, before feeling sad, realize that sadness is also simply a chemical, like all of our feelings. Our perception of existence is deeply flawed. We do not understand the reality in which we dwell, nor do we have the insight to realize what knowledge we lack. In theory, every occurrence can be explained by complex logic and physics. Dumb luck is only what we do not understand... It is a healthy ignorance that allows us to overlook this and other things.
I consider this and other philosophies often, my emotions compelling to me do so. What I have spoken of is only a piece of the sad realizations that often come from thinking to deeply, and I trust that if you search for them, you will find them. It's hard to detach yourself from humanity entirely (Something I am rather pleased to say I haven't done yet), but it can be done. Always remember that all life ends in death. All of our joys will be forgotten. There is no real purpose to life, and there is nothing that can be done about it. :P
The more you think about how insignificant you actually are, the more you feel like what goes on in your reality doesn't hold any real significance.
The more you think that your emotions are actually electrical signals flowing through an ape-computer in your skull the more you realise that what flows through it doesn't really matter.
Humanity places you on the earth, it takes over you and you wonder about it. Thoughts like this lead you to philosophy ideas, human emotion, and the size of the universe. If you are saying that it will take you away from humanity, that is wrong, because humanity is what created it and it's apart of it. Some people see thinking about life as an enjoyment. This is what creates intelligence, brilliance, and it's what creates curiosity into new discoveries.