Well, if you have to choose between dying depressed and dying happy.... well, assuming you believe in freedom of will. Otherwise you can't choose. :-p
But lets take a different look on the issue. Who said positive singularity will help you survive indefinitely? Whatever it will be, it won't be God and you won't be in Heaven. So it may take 3^^^3 years, but eventually you WILL die .
How many people feel despair in imagining a heaven (positive singularity) that they'll miss out on if they don't survive long enough? I don't think about it, but I already have plenty of reasons to like being alive.