anger and insecurity

I just can't sing anymore. Even when I'm not at home. Every time I think of singing I am attacked by guilt and the fear that someone will scold me/insult my voice and I just shut up. I haven't sung more than one or two lines for a few months now. I hadn't till yesterday. And the whole time I was singing I was feeling guilty and horrible.

And here I listen to my sister singing as loud as she wants. I hate my personality. I hate that I'm so weak. I hate that I can't take the pain of insult. How do I make myself comfortable with insult? If there were a cure...