What am I doing in this Small World?

I am Lily, I am a year eight student at West Lakes Academy and I have been asking myself one question. What am I doing in this small world, what is my purpose? Let me explain... what difference do us humans make in our society and beyond? There is you or me, a clump of flesh in our own comfort zone. Then there is our comfort zone, which is one of many in this whole planet. Our planet (Earth - if any of you didn’t know) is one of many planets, then there are dark planets. All these planets are in our universe. AND GOD KNOWS HOW MANY UNIVERSES THERE ARE! So, what difference do we make?... You pick one piece of litter up and drop it in a nearby bin, what difference is that going to make? Yes, you will feel good about yourself. And yes, your mood will then prevent others to feel happy like you. However after that, what do you do? You can’t stop all littering around the world by picking up a tin can? Can you!?