lol, when I first saw this move, I was like "You're using an engine, right?" Ur last move seem waay too devious for a usual player, and the opening was also played more than correct. I was playing all out of my mind, but i'm not sure if you also didn't use any databases etc... I was analyzinh that last position for like an hour and didn't find Qb6. But anyway, I'll trust you for now, and I play:
20.... Rd8.