Although I empathise with your lack of confidence, you should try and think about your shape positively.
A lot of women who have larger breasts curse them because they are uncomfortable, clothes never fit properly, men oggle them, and so on.
As a slim woman, the fashion world is your oyster, you can wear stunning clothes that emphasise you - and believe me, men will notice you!
Thousands of men either don't especialy go for bigger breasts, or like me, really don;t care, it's the person they arew interested in.
I understand that you think your confidence would improve with bigger breasts, but if you shine through as you are, you'll find that everyone accepts your shape, and you will too.