2003 Pontiac Grand Prix FUEL ISSUES

Recently, my grand prix gt started experiencing what I believe to be fuel related issues. My car smells strongly of gasoline, loses or burns thru the gas at a very fast rate, and seems to chugg along. It also idles badly and will sometimes have a hard time staying running if its on an incline. My question is if this could be because of the catalytic converter being plugged up, or if it sounds like a major fuel leak or if it is an injector problem. Or maybe even a combination of things like maybe a vacuum problem coupled with a gas leak. Please give me some advice. Im no mechanic but am extremely mechanicly capable. Thank you for your time and attention