If you're in a slump, where it's career or elsewhere -- give yourself a break, it's really, really hard to unslump yourself. This is why you need a plan and a person (or 3) to help you. Even if you're smart, successful, organised etc... people generally aren't very good at taking advice from themselves.
Confidence isn't some magical pill. It's not some inborn trait that is bestowed upon certain people and not others. And it's not something you get once you start a business, achieve a large goal, or finally find the person you're supposed to be with. This is exactly why the typical "fake it till you make it" advice doesn't work.