From my own personal experience, I find that gaining confidence is a tricky thing.
To have confidence, you need experience. To have experience, you need to start doing it. To start doing it, you need confidence.
It's a vicious cycle.
What is the solution? Gather all your courage and just do it. There is no easy way, no short cut. There is no pill that I can give you to make you confident automatically.
The first step is the hardest, but it's worth it.