I think it's Normal.
It's completely dependent on the friendship however. I would question whether or not you have feelings for the person, but this is purely based on personal experience and the beauty of hindsight. Regardless, I do think your current feelings are normal depending on how special the friendship was to you.
In my opinion, friendship itself is quite an ambiguous term because the modern day individual seems to have many types of friends. Referring back to my personal experience, I had a friend who I went through a really hard time with, they supported me and I supported them but our friendship was just not meant to be. It still sucks to this day (About two years on), but I accept it and I miss the friend I once had and I did go through the feelings and thoughts you experience.
Although, you didn't specifically ask for advice on how to deal with it, just try to remember that if it was meant to be it would of lasted and maybe in a year, ten years or whatever, when individuals mature and life experiences bridge over previous cracks in your friendship, you may rekindle your friendship. You also might not, but what happened is probably for the best currently, even if you can't believe it yourself at this moment in time.
Nostalgia is a wonderful thing, it often makes you remember all the good times you had with your friend, but not the bad times that broke the friendship.
There is no easy fix bud, just try to keep going and eventually time will fix your pain.
Hope you have a good day tomorrow bud and good luck, hope this helped in some way.