1997 Bonneville Problem..Please Help!!

My 97 bonneville SE with the 3800 V-6 (not supercharged) was recently having some loss of power problems where it would act like it was stalling or dying then would just fire back up to normal. It ended up quitting and would not start and had no fuel pressure at the check nozzle near the injectors. I replaced the fuel pump and fuel filter. The car starts great and runs great but now I am still getting multiple codes and the car does not want to move very easily and acts like it is taking off in 3rd gear or overdrive. I have not driven it for any long distance since this problem occurred (which was immediately after replacing the fuel pump.) because I did not want to damage the tranny. I did run the battery dead initially trying to start it when it broke down on me and when I dropped the exhaust to lower the tank I damaged the wires on the o2 sensor by the Cat and the bared wires were touching the protective metal cover there. I replaced the o2 sensor there and still the same problem. The codes the car is giving off are ...3 shift relays...EGR and evap something or another. It was giving the o2 as well but i have replaced it now. The car ran perfect before this and I find it hard to beleive that all 6 things went bad on the car at once. Any ideas would be greatly appreciated!! Thanks all! Craig :banghead:

p.s. I am unemployed and really cannot afford to take it to a repair facility.