I made the foolish mistake of running out of gas. Well technically, I did make it to the gas station in time. However, two minutes after the last fuel bar disappeared, I behain hearing sloshing noises. After I got fuel, the sloshing noises continued. And now I'm getting terrible fuel economy.

 

what year is your car? its possible you picked up something from the tank that is getting into the tank pick up (there's a screen inside the tank) or fuel filter. Otherwise it may be a bad tank of gas or a pump that's on its way out... You can try changing the filter on your own or test for fuel pressure at the injector rail (there's a small schrader valve there).