In the absence of religion, I found myself being a completely nihilistic until I read the works of Camus, who recognizes the absence of inherit meaning, but also says that humans create their own meaning. The universe is an abstract combination of particles and waves. Humans observe these waves as color, and the particles as objects. We create beauty by, for example, arbitrarily describing a mountain as beautiful, there is no beauty until we look at that lump of atoms and say it is.
Everything we do in the modern world is synthetic: go to work, watch tv, eat, go on the internet, etc., but it doesn't mean those things are not worth doing; if someone derives enjoyment or meaning from those things is it not worth doing them because they are synthetic? I think not, and I have accepted the chaos and absurdity of existence and what keeps me going is humanity in general. Our art and cultures come from seemingly no where, and I think that's beautiful. My new purpose is to help other people because I have recognized that everyone is the center of their own universe and it is slowly becoming my default way of thinking rather than I alone is the center of universe.
I want to educate people and make others see the light. We are all groping blindly in the dark maze of existence, and occasionally some one or some thing brings light into it and helps them keep going. Whether it be religion, a person, a team of any kind, or humanity in general, it is paramount to fine "the light." The light that I have found is a deep love for humanity in general, it all its glory and its evil. What keeps me going is the desire to make humanity better, to make people see that everyone is an individual who thinks and feels just like them. I'm glad I have figured out my meaning in life, at a relatively young age (Although I am painfully aware that everything is different when you exit adolescence, but as of right now, I cannot even begin to fathom what life outside of high school will be like for me). So hubski, what keeps you going?
I live my life for no other purpose than to bring entertainment to others - and hopefully from that, education and enlightenment. Not "enlightenment" in the sense of knowledge or understanding, but in the sense of literally shedding light on or brightening their moods. My beliefs are...strange, for lack of a better word. I strongly enjoy and agree with most Rosicrucian and Hermetic ideologies, but there's something about chaos magic and its base principles that really speak to me. When lumped in with Freemasonry and a Catholic upbringing, there's some muddling of beliefs.
My overall meaning comes from a variety of places, as noted above, but I guess to determine what I derive it from in the most base terms would be the following: I attempt to be a builder of spirituality and morality for both myself and others I meet. I try to blend sex, death, and humor in with more traditional ideals to create an adapting system of understanding and belief that won't become stagnant with time. I believe that magic exists in the form of the imposition of one's will on the universe. I acknowledge that we are all immortal in the sense that the matter comprising us and the energy we generate and expend has been around since creation and will remain until the end of all things. I do not fear death, and my purpose in life is to brighten others on any plane we can connect on - mental, emotional, physical, or spiritual.
I'm glad to hear you've figured out your meaning for your current stage in life, but don't be afraid to embrace change. As you continue on your journey and broaden your worldview, there will be many moments and events which will impact your character and further refine it. As you mature further, your purpose for living may change. Do not be afraid of chaos, be respectful. Embrace the growth, even if it is painful at times. Above all, be honest with yourself about who you are. We are our choices.