Rewatching the ep, I think Jamie had a deathwish during the battle. Dude didn't retreat when Bronn said, picked up and tried to fight on horeback, was out in the open with the archers trying to fight the dragon directly, then trying to to charge Drogon and Dany in a suicide attack. Don't think he wants to be back around Cersi anytime soon.
I think it's more likely that he overcompensates for the loss of his hand.