since doing contra (highly speculating), it is best to predefine a stop loss before entering the position (also a level for profit taking, at least for some portion of the whole position).

A lot of times even a well defined stop loss point may not be followed when executing the trades, either because of lack of discipline, or maybe becuase the stop loss is already penetrated on the opening gap down. we human most of the times will pray for a rebound which may not happen in your trading time frame, especially for short term contra trading.

I guess the best we can do is to train our discipline or reduce the position size.