I have never know what I have wanted to do as a career. I currently work in a mortgage brokers and I think although I don't know if it's exactly what I want to do, it would be ok and I think it would be worth training for just to get more money and it would mean I could get involved in more conversations at work with my colleagues. However, I lack confidence so much, I hate talking on the phone and I harfly speak to my colleagues, I can't show them the real me even after 5 years here. I could get my employer to pay for me to train as a mortgage adviser but I don't want to get qualified and then find I'm too scared to speak to clients. I don't think I'm very good at explaining complicated things simply either which mortgage advisers are supposed to be good at and maths isn't my best subject. I've been trying to improve my confidence but its not working and I don't want it to hold me back in my career but it is.
Sounds like you need to go on a course to boost your self esteem and confidence, something like an assertiveness course/training maybe?
If you talk to your boss he should, hopefully and in theory, pay for you to go on it. (not him personally, I mean the company should)
I don't know where you live/work but I googled assertiveness courses and it came up with quite a list.
Good luck :-)