Are we what we think??

One of the questions which always bothers me is: What exactly is our purpose to live? What exactly are we here to do? And are we doing it? And why are we doing what we are doing? And whether something called destiny is present in our lives? If not then why am i in the place i am instead of yours? And if so then who decides the destiny? What bothers me most is this scenario which i frequently imagine. Consider yourself in the position/location u are right now. Now just consider yourself from the eyes of a lizard had it been on the ceiling of the room you are in. Easy... Let me make it more difficult. Move the ceiling a little higher. Or maybe as high as you can imagine. and now look through the lizards eye again. And remember only the ceiling goes high. The walls of the room do not expand.... See how small you've gone. Well we've not reached even half of what we know. Consider the ceiling to be transparent or better if you can imagine your room without the ceiling. Consider an aeroplane which is just flying above your head. And a five year old kid is looking out of his window directly at you. Do you think you are the only thing visible to him? Just try to imagine the perspective of his gaze. Well if you are able to do so let's take a huge leap and land on the moon. The only manmade thing visible from there as they say is Great Wall of China. What happened to you? You are just one of the people whom the astronaut on the moon can't even see. Want to go further?? Your wish... You can go on to the other galaxies and much further and you'll find the worthlessness of yourself. I'm not saying you are worthless. What I'm trying to say is that when i reach such heights i find myself negligible as compared to the huge scenario in front of me. So i wonder. What exactly is my purpose of existence. I already have written an entry on it. But one of the gruesome realizations/question that comes to my mind is that...
From the eyes of the five year old kid in the aeroplane the scenario seems similar to what your eyes see when you look down at a cockroach. I didn't want to use this scenario but this is what exactly comes to my mind. So the people who have problems in coming to terms with this scenario... please do not read any further. And i apologise beforehand if i hurt someone while describing my thoughts any further. How much difference is there between the two scenarios i just mentioned? We are populating as much as i guess with the same speed as the cockroaches are or can. Most of us think that they are making a difference to the society or the world but they actually make the same kind of difference on a larger scale as an intelligent cockroach does by making an artificial leg for a leggicapped cockroach. Most of us just care about our families and relatives and their well being. In fact so do cockroaches. Most of us have just money on their mind(which after a long discussion can be equalised to food) and so do they. Can you imagine whether cockroaches can play football or not? How sure can you be that they do not build football fields hidden from us? Or that they do not have hangouts where they go on special occasions? Of course they will be special to them and not to us. Just like our sports are special to us but not to a lot of other people. And by the way i guess that i think about cockroaches instead of any other insects because i hate them a lot.
Not going into any further details but all this makes me think if i am like a cockroach to someone just like a cockroach is to me.