Honestly forgetting about a loss is hard especially a loss that happens after you've chased a loss. More reason why you should not gamble irresponsibly. My estimation um if you are is all it takes for me to forget about a loss and to do this I always stay busy, that is a trick. If you don't give your mind something to think about and your hands something to do your mind would always ruminate over the loss and it is absolutely, pointless. Stay busy.