I have had my pickup since 15,000 miles... haven't had any trans. Problems at all... suddenly on Friday, I noticed that when you took your foot off the accelerator, the trans. Immediately seemed to be trying to downshift into too low a gear. After this,when starting from a dead stop, as you accelerated, trans. Felt like it was in neutral... if you "eased" down it gave you the sense that the fluid pressure had to build up, then the truck would move... Once moving, it seemed OK.. and shifted OK. I thought trash in the system might be plugging a return line or something... I bought a filter kit and fluid and was going to change the fluid... when I dropped the pan, there were a few shavings and 4-5 small "roller" bearings in it... I stopped there and put the pan back up.
Any hope here?

Sorry, no hope for that transmission.
That sounds like a catastrophic failure of a roller bearing housing.

Small solice: this isn't likely operator induced... I don't think you did it. The failed component was simply the weakest link.

Chances are, some of the debris has moved around internally and is causing the shift valve to no longer cooperate.
I would recommend a trans shop. Perhaps some repairs can be done, but be prepared for them to recommend replacing the assembly. I would concure, simply for peace of mind and warranty reasons.