This was a disaster as I completely underestimated it... I was up to 5000 shares short when it squeezed HUGE and I had a very large unrealized loss. I had to hold this a long time and eventually took a much smaller loss. I actually made money shorting it including my other trades, but still took a big risk here. This is exactly why I rarely trade with size, but I was reckless on this trade. Luckily I lived to trade another day.