Thanks for your responses. (I kind of want to delete everything I wrote below because I sound like an angsty teen, but it's just what's been weighing on my mind lately.)
....there is no purpose if you are talking about "greater universal truth bogus trademark waffle" purpose.
However you might consider the ridiculous odds of you being alive as awesome enough to warrant "living".
I don't know what I mean by purpose. I don't really mean anything I guess, it's just kind of depressing that there is ultimately no meaning to anything that I ever do beyond making myself and others happier for the short fling that we get before dissolving into our basic elements. I used to think that people who kill themselves were simply insane but I think I can understand it now. If life is beyond enjoying then there's no reason to carry on with it. I still enjoy some things in life so I won't ever do that.
I don't really like thinking of the past in terms of probability since that was just what happened. Predicting the future is one thing, but once it's become the present and then past, it's just an interesting aside. It's amazing that any of us exist, but since we do, it's already accounted for.
I am plagued by existentialist angst, .....there is no fucking point, but then I remember that I do not need a point to exist, I just exist.
If as I believe this is the only chance I will get at this, then for me personally it seems stupid to require "a point" in an obviously random generating universe, instead, I just remind myself to "just get the fuck on with it".
I imagine this is what I will eventually come around to. It doesn't really assuage any of my desires that what we do has an impact on anything anywhere, but what I want isn't important.
So my existential angst becomes subdued under deliberate active pursuit of the experiential, the sensual, the (to my brain filter) beautiful.
Perhaps my extremely low tolerance to boredom helps, I have grown into an active state of escapism as life, and the most social contracted position I take in this pursuit of my will, is the second half of my stated intent "to live as happily and harmlessly" as possible".
Given this our moment in evolved monkey "civilisation 
" if life is supposed to have an external eternal point, it is only for the dull.
The real point (if any is to be found) is self realisation and self realised.
Escapism... I guess that's all we can do.
I grew up being told that everything I did was part of a great and beautiful plan. Every small thing I did was for the greater glory of an eternal cause. Kind of a letdown to discover that none of it exists.
I can hope that I'll pass on to another life but that's as far as I can go without feeling I'm deluding myself to get on with living. Phenomenologists try to move beyond Cartesian skepticism and existential doubt, but at the cost of objectivity. I just want to be honest with myself about everything and contriving a purpose for myself seems hedonistic at best.
I'd only add this: We're only here for a short time, and we only get one turn on the ride. Have as much fun as you can. Enjoy moments for what they are rather than what they mean. Contribute to the things that matter outside yourself; your family, or welfare of others, so that they too may enjoy their moments more. Work hard so that you may maximize both the satisfaction of doing a job well, and the money or security you may need to keep on enjoying those moments.
There really is no future nor past. There never was. There's only the 'nows'.
Just my .02 as a fellow atheist.
This is a useful mindset to have but it's not helping me where I am right now. This is what I felt before as I described in the OP. It's a lot of effort for a whole lot of nothing in my mind right now.
You owe it to the fact that you can contemplate meaning at all to be as meaningful as something meaningless can be. In other words, look at what you really are. You are not a star, billions of years old, only to die in a billion more. You are a life form. And while the elements that form you will eventually be broken down, shifted a billion light years across the universe, the thing that makes you you will never exist again. Your consciousness. Your ability to appreciate music. Your ability to love.
If you don't do something with that knowledge, you do a disservice to all things, matter and energy alike.
As far as I can tell nothing is keeping track of what we're doing or will ever do. Maybe another group consciousnesses will rise up elsewhere in the universe and find what we're doing, but everything will just collapse in on itself again at the end of the universe. Will that reset everything? That's why I think eternal recurrence is interesting. It's really the only thing I can think of, besides the obvious 'just have a good time', that someone should try to move forward with their lives. If you're miserable this time, you will be miserable the next time!
Urgh, sorry, I don't know why I even made this thread.
