This is an experience that in my view emphasizes the importance of educating children early about the way things are in life - constantly moving - and that things never really come to rest for us until we die. Religions and idealistic philosophies teach the opposite - that there are permanent ideas and permanent pal-gods who will be with us not only for our whole lives but forever in eternity. One natural effect of that is to think that things will always be the same, and that in fact we'll all spend eternity united with our loved ones in heaven, so really who cares how we spend our time right now?
If people from a young age were taught the way things are, it would be a lot easier to keep focus on how important each day is, and how we have to expect change and learn to be comfortable with it.
I know I feel this way (about losing the past) regularly and it seems to just get more acute as we get older.