missing an aspect of the past...

Tonight I had two encounters, one at the grocery and the other on the way home. It was subtle and actually impossible to detect if you were observing it from the outside. I felt it on the inside, a twinge of reminiscence, a twinge of yearning and missing. I don't like when I feel that way. I always feel uncomfortable about feeling it. I wonder whether I am alright? I get defensive, and I say to myself that perhaps it is normal. I also say to myself all of the things that help me to move past the feelings.Things like...You'll feel this way again, don't worry, and it shall be greater and longer and worth my while.
I don't doubt myself when I cheer myself up with those affirmations. They help. Yet,tonight, there was something else in my gaze as I saw the two separate couples, doing the unremarkable things that life puts forward. They were both just standing together. The first family, with their two children, and it turned out that I knew the person from ballet, years ago.
The second person was standing with her husband, waving to someone who was leaving their driveway. The assurance of the other person, standing there, I felt the value of that, the importance and intimacy of knowing that there are things shared.
I think that I have to come to terms right now with the fact that I have to stop feeling so thrown by love,by lasting relationships that are not my own.
How do I begin to fix what is clearly a hole that I feel inside? I thought that I was doing so? But when I get to this place, I remember that I am still bruised. I am so tired of feeling that I am still hurting. I don't like it one bit. but I don't know what to do about it.
Part of me replies, don't be so hard on yourself and another thinks, get back on the horse. I really do not have an answer.