2002 Chevy Silverado won't move in any gear or Reverse?? Thoughts?

1. Friday I'm driving to work like normal. Truck is doing fine. Stop for breakfast. When I get back in truck isn't accelerating properly. Less than a mile down the road I can't make it up a slight hill. I put it in first and make it to work (barely). As I pull into work It sounds as if something is dragging on the ground but on inspection nothing is hanging.

2. After work a coworker takes me to get some gas because the low fuel light is on and I ran it with the light on a bit longer than I normally would. Immediately it starts up and seems to drive fine. I'm thinking this was the issue after I put a gallon in. I drive around the parking lot and wave her off. I get down the street and it won't accelerate. I'm stopped at a light and can't go anywhere. I shut the car on/off, and it drives just enough to pull into a nearby gas station. I get it towed to my place.

3. I've tried to unhook the battery and then hook it back up to see if it could be reset. No luck.

4. Today I rent an OEM Tools for Professionals Brake Reset +Tool. The best I can tell, there is no code that has been stored. It seems kind of complicated.

5. Just for kicks, I started it up. I tried reverse. It worked. I moved forward. It worked, I drove around the block and it quit again. It turns on and the engine starts, it won't go anywhere.

My Dad spoke with a mechanic friend who thought it sounded like a Transmission Module Control for what it is worth. Thanks to all!