Of course, you have to make your own meaning. You are a vehicle for your eternal genes. That is a fact. But you are also thinking being that can comprehend the vastness of the cosmos or the concept of time. You can love and be loved. You can share your thoughts and memories with others. You are part of a phenomenon that may have never occurred before. That is also a fact. But whether you make the most of it is a personal choice.
You mention several things which are positive (comprehension, love/loved, experiences, sharing) and that making the most of them is personal choice. I agree with you there and I certainly do make the most of the things which bring me joy (family, friends, nature etc). I recently did some personality tests (thankfully I didn't fail :) as part of a set of tests my employer supplied. The results of these things I normally place on the shelf with horoscopes but this one genuinely surprised me. Along with some other things it said my approach to concepts was 'contextual'. Maybe its the confirmation bias talking but I think the result was pretty spot on. Its all about your context, its nice to look at the brightside but you need to glance at the dark bits every now and again to keep your perspective. They both make up the whole...