Is it normal to still be affected about doing so badly in school?

I finished school about 10 years ago, yet whenever I'm in a really depressed low self-esteem mood and I end up thinking over all of my faults and failures, one of the things that always crops up is the fact that I did so badly in school. When I was much younger I always saw myself as smart, since I liked reading and didn't like causing trouble. I was often called a bookworm, which I really appreciated. And so I really hyped up to myself the importance of being smart and doing well in school and going to college. But then when I went into secondary school, I was terrible at it. So then I started feeling like absolute shit and my self-esteem started to wear away. But even now after all these years, after I've come to realise that most of the time doing well in school doesn't necessarily equate to intelligence, it still affects me. It's still something that really makes me feel shit about myself. Is this normal?