No power after replacing the catalytic converter

I have a rough idle and when I put the gas pedal to the floor it does not pick up the speed at all. I have changed all the plugs and wires, I changed fuel filter. The idle seems a little better after the fuel filter but still no power. One day I drove about 20 miles when I pulled in a Quik Trip and all of sudden the truck was jerking only it wasn't jerking forward it was side to side like someone was shaking the truck and all the gauges on the dash were all going crazy and then the check engine light came on. Right after this incident was when the plugs and wires were changed, new catalytic converter was put on and then it started the no power. It really seems like something is plugged up. Tired of searching please help.