Firstly I'd have a polite sit down with your boss & voice your concerns in a chatty conversational manner, but at the same time let him know you're serious. Your manner will allow him to be more open & you'll more than likely get an honest answer. That should enable you to form a more fact based opinion of your current standing in the company structure & in your bosses eyes. From that point you can play it by ear really & decide your next plan of action.
I will say though, if you can't move up, move on.