2000 Grand Prix GTP only moves when put in reverse

I have a 2000 GP GTP. I went over a speed bump to fast one day, and parked my car. When I got back into the car the next morning, I tried to put my car into drive and it wouldn't accelerate or move. So I put it into lower gear, 1st to be specific, and the car moved normally. I drove like that for a few days with no problem. Then days later I did the same thing, went over a speed bump to fast and now the vehicle wont move at all unless I put it in reverse. CAN ANYBODY HELP ME?!?!?!?!?!?

Are you saying, the car only moved in 1st gear manual? It didn't shif into second, third or fourth?

Have you checked the underside of the tranny and pan, for a crack/leak?

Checked the fluid level?

Scanned for codes?

Yes it only moved in first gear. I can shift into any gear, but the only gear it will move in now is reverse. It was working in 1st gear for awhile, then I went over the speed bump and now nothing but reverse will make the car move. I changed the fluid, havent scanned for codes yet tho.