This is going to sound really sad but over the last few years I have suddenly started thinking a lot more about the past, about people I have not seen in 20+ years and having this intense sort of nostalgia. I am over 40. I thought it was just me but several of my friends have also said that they have this too and that they have suddenly had the urge to contact people they haven't seen in years or start listening to music they haven't played in years. Is this common?