It is not low self-esteem. I know exactly who I am, and I am confident in that. That's why I don't allow someone else's lack of urgency or enthusiasm towards me to change my character and principles.

Actually, constantly "matching energy" is the peak of low self-esteem because it means allowing other people's behavior shift your entire personality. If every time your true self is not received positively you become someone different, you're no longer acting from your own convictions, you're living life reactively. You have no self esteem because you don't even have a "self" to begin with.