I want to do something amazing, something really big, but what?

I KNOW I am not the only person who feels like this. But Im yet to meet another person in real life who agrees with me. 
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I want to do something amazing with my life. I don't just mean finding my dream job, traveling the world, or helping a few people in my small community, or "finding god/peace of mind/inner peace/etc".
Those are all great things that I do eventually want to do at some point in my life. But I want to do something big, something monumental, I want to reach out to millions of people world wide. But how?
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I'm lost, but I can't help but feel I have a greater purpose in life. That I'm meant to do something huge.
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I have many ideas, from inventions, to outspoken art, to youtube videos. Those can all eventually lead to huge changes in the world after years and years of work. And I'm more than willing to commit my life to whatever it may be. But I haven't been able to find that niche yet. Nothing has felt "right" yet.
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I write all my ideas down, and when I get any sort of inspiration about something I start following it, take the step towards it, hoping to find my bigger purpose. I guess this is all I can do. Live day by day, till I find whats missing, what I'm supposed to be doing, or the direction I'm supposed to take something I'm already doing.
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Who here has the same feelings? Have you found your purpose?
Are you on the path to doing something monumental?
Please share your story, experiences, thoughts on this. As I know there are many people who feel just like I do, and are stuck just the same