This question can be very tough to answer, but believe me, many people won't stop thinking of that if it happened to them, so I want to know your opinion about how you would feel if it happened to you.
I'm not sure how "many" is the people who can't stop thinking about it, because me, I've had an experience just like this many times already and it's even worst since I had the money and the only thing that I should need to do is to place that money as a bet for the team that I have predicted to win.
Not only in gambling actually, but with life in general. Have you ever had an experience where you are doing something that you really love to do to make a living? Like turning your passion into profit? But you stopped in the middle of the process because you think you don't have enough talent and skills to pull it up successfully? Well, that kind of a similar thing. Therefore, that question ain't really hard to answer for me. How'd I feel with that certain situation? Well, normally as a human, you'll feel frustrated and disappointed but you gotta move on and move forward, you just can't dwell with it for a long period of time because that feeling will get you nowhere as it makes you feel demotivated.