1999 Chevy Prizm I have never heard of anyone having this p

My boyfriend and I were driving down the road and we started to hear a knocking sound. As we were pulling of the road to check it out, the car basically lurched and then died. When we opened the hood, two of the spark plugs had jumped out of the engine and were just lying there on top! We managed to get them back in well enough for the car to drive, but they do not seem to fit right anymore. The car still lurches when we are in drive, especially with the brake on, and it is burning gas like crazy. The engine light is flashing, and I'm afraid there is no repair for this problem. Please help me!