Dont consider yourself in HUGE trouble. These days gas seems to be getting cheaper and cheaper....Once you've run most of that gas out, and filled up with some new stuff, You can unhook your battery to reset the light or have a tech do it with one of those handheld units. It was probably the gas, if it wasnt then possibly its your spark plug wires, if one of them is going bad, it can cause a misfire. Just ideas