Maybe work on your physical health. Start exercising/working out with some goal to reach like losing xx amount of weight. Or maybe walking/running/biking/swimming with a goal to be able to reach XX mi/km or whatever. Or train to be able to compete in some amateur walking/running/biking/swimming event. Or take up an organized team sport to help give you more structure to help keep you at it.
Sure, this or couples of other things could work out too. if you're determined to stay away from gambling, but most of the folks aren't determined. that's why they gamble again and again and lose their hard earned money.
It is not just based on determination. It is about the support. If you are so addicted to gambling, you sure are unable to have the determine to quit from it cause you are so used to gambling. It is just like asking you not to use internet but you are so used to it that it is almost impossible to quit. Take note, quit means forever dont use.