2000 GMC Sierra

Truck was running fine. I jumped a dead battery using my truck, now it won't start. The engine turns over, my all accessories (lights, radio, ect) work fine. I think it is a fuel problem because initially it would start for a few seconds, but progressively got worse. Now the engine just turns over. Tried replacing the fuel pump relay, did not help. I cannot hear any fuel injector or fuel pump activity when I turn the key on. What else could it be??
2000 GMC Sierra 1500 Vortec V8 (4.8), 4wd
Help!