No gambling is not guarantee for losing. There are a lot of people who consider gambling as their mean or earning money, and in fact they are making money from gambling for a long time. They have gambling skill, knowledge and experience they know all the trick of gambling and defiantly they may also have good luck therefore they are winning gambling bets for most of the time.
The number of people that lose compared to those that win is incredibly higher than what you are expecting. Therefore dont even think of trying to be rich from gambling alone. You could be getting some money from that however dont ever think that alone is enough to sustain your life forever because it is not