I guess it's safe to say this is normal since so many of us are experiencing this.
A couple of years ago I went to my high school reunion (40 years), well of course that was a blast from the past. But since then I once in awhile think of a couple of people who have passed away in our class. They had nicely done a table with their pictures and each had a rose lying in front of them. Every now and again one of them will pop in my head, especially a couple that I had gone to school with since kindergarten........they all died young as I am only 60. It brings a sad feeling over me even though I hadn't seen them since high school. Feels strange......