I think it helps to focus on the positives of a situation, sometimes.
I have noticed that in the last 5 years or so I have really felt that the passage of time is speeding up. I will be 32 this year.
I don't particularly believe that belief in an afterlife is important, it is important to live our lives as best we can, as we are here on earth, right now. Just as what tiredlady has said.
I don't believe that god has a plan for us, I actually think we are following our own plan. This makes me 'get on with things'.
Bad things that happen to me - later on, perhaps years later I can reflect and realise what I have learnt from the situation. I can derive comfort from knowing that I am a stronger person (sometimes) just from having experienced certain things. This can allow me to support or assist others who find themselves in the same situation.
Everything is changing all the time, change seems the only constant.
OP I know you said you don't believe, but anything is worth a try to make you feel a bit better? I asked the angels to slow my perception of time down. Yes, I know how crazy this sounds. It has worked for me.
I lost my father after a very short sharp battle with cancer and my son was born only one week before. There was no time for anything. Sinking into bereavement on top of other very painful circumstances made me miss out on a lot of good experiences. I had to do something to help myself, I asked the angels for help.
Epheremal we may be, but all the more reason to live for the moment.