A high level of confidence and self-esteem is normal, but I don't think that makes you one. It's possible to have some of the tendencies without having NPD. It takes a lot more to make you one.
I dated a narcissist, and once I relationship ended, she was actually diagnosed with it. I went to hell and back with that relationship. It was like dating a person with two personalities. One day I was cool, and the next day if I said anything that she didn't like, I was the devil and a shit load of other stuff. Dating a narcissist is one of the worst things you can do. Run as fast as you can. To outsiders looking in, they have the type-A personality. They appear to be all around good and decent people and charming, but behind closed doors, they are somebody different. She would describe me as being everything she wanted, but she was always looking for more. No, she wasn't polyamorous. When she cheated, guess whose fault it was? Mine. She wouldn't take responsibility and never did apologise. I had to get away from her. There comes a point where you start feeling like you've lost your mind, and you're the unbalanced one. No matter what you do.
You have to shower them with constant attention. Narcissists can't love the way a normal person does. They only love you if you love them back, and once you stop, their idea of love dies. After a break-up, some want to cause you pain, so they defame your character and slander you. Let me tell you how crazy this broad was. She threatened to mail me something that she knew I was severely allergic to. I guess she wanted me to end up in the hospital because I left her. I ended up having to get a restraining order against her.
Everything will always be your fault. They are never sorry about anything they do. They have no empathy. They can look you in your face and lie, but they will never say sorry. They will sit there and watch you cry with a straight face. They know they're hurting you, but they don't have the ability to care. They have no problem using people to get what they want. It doesn't matter who gets hurt in the process. People are just stepping stones. They generally exhibit tendencies of other personality disorders, and if they don't seek treatment, you have no chance. An all around nightmare.