Sad I'm getting older

This is such a stupid thing to be upset about. I believe aging is a privilege and not something to get upset with.

But now that I'm approaching my mid 30's, I'm actually feeling so upset. I've been looking at the Facebook page of my primary school, listening to music we did as children and such, and instead of feeling nostalgic and looking back on those memories fondly, I'm quite depressed.

Is this normal?

I had a very happy childhood and then things went downhill when I was about 13. Things have never truly been as good as they were when I was a child and I guess I'm just sad that I don't have really, REALLY good memories other than my childhood memories.

Am I the only one?