In my dark journey through life I've been through some pretty unimaginable things -- I've actually come to the point that I've pretty much stopped telling people about my life entirely simply because a lot of it is so extreme most people can't even grasp that my experiences could possibly even be true -- my life has left me to become very nihilistic.
Because of this, I don't view "purpose" in the conventional sense -- I have this really zoomed out view where, when you look far enough in any direction, ultimately, there really is no conceivable purpose to anything -- you push a domino to push a domino to push a domino for an outcome which will either end when you end, or create a wave which will disperse and inevitably lose it's form over time and return to the "ocean" from which it came.
Ironically, this nihilism has made me a much better person, made my intentions much more pure, and my actions more sincere -- I understand now that any purpose which I adopt will have no "reward" for me, and this emptiness allows me to be truly selfless in any "purposeful" act, as it is done devoid of any ego.
There is a quote that I can't quite remember verbatim that states something to the effect of, "the best form of suicide is to serve others," meaning, you free yourself of your own ego and pain when you minister healing to someone else, so, the only purpose I find is to "be here, now" and affect those I come into contact with in the moment, to give peace or justice for the sake of whatever temporary satiation it may serve another.
What gets me out of bed in the morning? The realization that, many of my "best days" are already behind me, and the fear of not making the most of the few I have left.
What makes my life "significant?" Ultimately, in the big picture and grand scheme of things? I don't believe it is significant. But in spite of that, I can say, that despite how temporary or small a part we play in this world, I know that no one will ever be me. No one will have in them, what I have in me, or ever have what it takes. So if there is any "significance" to be found, it is in the authenticity, and diversity, of our unique being.