What symptoms would a lose fuel filter or fuel line leak have?

I believe that the mechanic who put my new fuel filter in may have messed up and cracked an old fuel line or perhaps not put the the filter in all the way. The car was acting alright at first when I drove it away and steadily the car started to lose power. The idle became more rough over time and the car began to run rough at higher RPM's. It seemed like the more I drove it, the worse it got, to the point where at an idle, the engine was shaking really slow as if it were about to stall out. I parked the car at my house and when I came back from work, there was a small pool of gasoline under it. I let it sit for a while, and the gas stopped dripping. I am uming that the fuel lines just emptied on to the ground. Would these be symptoms of having low fuel pressure due to a cracked line or lose filter? I jsut want to make sure there is not a serious problem with my car. Its carbureted btw.