If you have this kind of mindset when you're gambling "ALL THE TIME" even though if you're losing, you're just fooling yourself so that you will not feel any regret or disappointment but in reality, you feel bad for losing money.

Being positive in gambling is completely fine, but sometimes, not feeling positive especially if you feel that you're losing is also fine because like what I said, you're making yourself a fool if you're doing that and you said it as well that if you think positive all the time, you feel overconfident. At the end of the day, it will all comes to mindset. If you reached your limit, stop. If you're on a losing streak, stop. Not feeling positive when you're gambling sometimes is good because it can be a blessing in disguise for you so that you will not gamble anymore hence, prevent further losses.

As for me, no I haven't, and I don't think that I will ever be on that situation.