Only a few people who can win over and over in gambling and that person will have much luck which can give him the chance to win. Having good knowledge will not help if you don't have luck because the luck will be the one factor besides the other things that will determine. If we lost in gambling, especially lost big money in gambling, we need to think twice to continue or to stop gambling. But the best solution will be to stop gambling for a while, so you can refresh your mind by taking a relax. If you can accept the loss after you stop for a while, you can know if your luck will not always stay beside you.
It's quite unrealistic to believe that there really are some person that is lucky. Because for me, everyone could be lucky at a time, it is just that, some people wins allot because they are atleast trying their luck often. But the percentage of those who won too much in just a small amount of game is too low. That means that if we cannot win a jackpot by playing small amount of games, we should try to play allot and lower our bet.
With regards to whether to continue or not when lost, there is a strategy which is called martingale, basically, doubling your bet after losing in order to get back your money fast.