There's a big difference between AmDram and Pro, sweetie. It's probably worth going along to some open auditions (check out trade papers like the stage for where and when) and seeing what sort of standard you're at in comparison to some of the other budding up and coming stars. If you have a confidence crisis, then it's time to get going to a performing arts college (somewhere like Studio Centre for dance or GSA for singing and acting). If you feel that you're at the same standard then keep going - just remember that for every job out there there are teh same 300 boys going for it too.

Might be worth getting an agent to try and come along to your show (Hello! Dolly is a good show to workshop). It's then a case of getting feed back here there and everywhere.

Good Luck