non-confidence

Why lack of confidence is not logical:

Q: Are you confident about yourself?
A: No, I don't feel confident.
Q: Do you feel confident about that?

A1: Yes, I do
- which means that you feel confident about something. You can use that as a motivation for yourself to bring up your confidence.

A2: No, I don't.
- which means that there are times where you could feel confident about yourself.

Positive reinforcement is everywhere. You just have to open your eyes, pay attention to it, and expand your awareness.