Forgetting your loss is not that easy mainly when the loss is huge, and you know wins does not easily come, therefore it takes a while before I forget my loss, since I don't have a choice but what I do after such experience is to take a break for a while, then I will come back to gambling, but if the loss is small I just forget about it and carry on withy gambling activities, it does not take me any thing.
I just suffered a significant loss in a gamble I played last night, but I didn't think much of it because I didn't use any capital at all, meaning I didn't make any deposits. I found a long-standing casino site that offered cashback, so I played there and managed to make a profit, but it soon disappeared again. I wasn't upset because that was inevitable, so I just accepted what happened and didn't dwell on it.
Unless, perhaps, there was an initial deposit, then we would think about the loss, or constantly think about it. The key lies in our own perspective on gambling.