Time and life..!!

It's so much difficult to face situation where you know you have only few days to live your life. More than half of days goes into overthinking,  nervousness, stress, tension and worries. When you realise that these stuffs are not going to make your situation better instead will make worse, and the then remaining days just pass on like as if we just started living freely, faithfully and happily, but at that point you will realise, you just wasted your precious time in thinking and doing nothing you liked.
Why it's so tough that we know we don't have enough days to live fullest then why it happens??
Really it's that difficult?? I guess, it is !!  Why we hold on the things that were so special for us, but for those special things we are no longer important and we know we will not be loved the way we were used to and even though we know we have no time, then why??
"Time is precious but life is more than that"..