Try just enjoying life and good fortune, and if you are believer, give thanks to God and put everything in his hands. Wasn't Jesus the one who said sparrows don't worry, and neither should you?
I think purpose is a reflection of man's overblown ego.
I have no clue what my purpose is and I get up in the morning and go about my business. Animals do too. The earth keeps going endlessly around the sun and the sun around the black hole in the canter of our galaxy, and our galaxy rotates around the local group of galaxies, etc. all going around in circles...for no apparent reason whatsoever.
[absolutes] I know they are necessary to fully use reason/logic in determining human decisions
I don't think they are necessary at all. If anything we sue them to force our beliefs as true and judge others as false. They are theoretical constructs that "explain" things we cannot comprehend, man-made constructs, speculative tales.
Do you think we are any lesser because we don't know why gravity exists? Or higher because we figured out why it rains? I submit it makes no difference whatsoever.
[if an absolute cannot be known by reason, by which means it is known?] You are not frozen, you have purpose and values. So you know or act as though you know absolute truth/values. Find what these, maybe one, are - a simple exercise will work - and ask yourself the same question. I think this is the most useful answer.
But they are not really absolute truth are they? They are human constructs we are crazy or even stupid enough to believe to be true. I don't know what my purpose is. Do you know what's yours? And if you do, how do you know it?
I remember a comic book: Turns out earth is a farm for humans who are grown for their eyebrows which are of high value in making coats for an alien culture. We're only a few thousand years away from harvest.
But that's not the purpose I'm talking about. What is our purpose to ourselves in our own life?
This is tied to what we value, each conditional value dependent on another and finally an absolute one - something we value inherently, in itself. Something that, all other conditions being equal, is more valuable, better than, than its contrary - to us.
We can follow our own trail of conditional values to learn that which we value absolutely.
I would guess that for you we would likely quickly end on either truth or knowledge.