Welcome to the Weightloss Forum, Kyzalie.
Every person is different and needs a slightly different physical and mental approach to losing excess weight. Up to now you just haven't found the right combination that works for you.
I suggest you examine your past weight-loss practice runs and and find what they had in common that made them unsustainable. Personally, I'm of the opinion that the old saw "if at first you don't succeed, try, try again" is rubbish. My personal motto is "if at first you don't succeed, don't try again - try something different!"
If you can figure out what exactly the problem was - such as boredom with bland food, expecting instant results, or whatever - then you can devise strategies to defeat it.
The simple fact is that losing weight is simple - create an energy deficit to force your body to
burn up" fat stores. The simplest way to do do this is to eat less than you need. Of course the devil is in the detail and there are lots of other issues that then spring up such as poor nutrition, combating muscle wastage, weight-loss plateaux, boredom, portion-size creep, and so on.
There are plenty of useful articles on the website attached to this forum. Read them. Educate yourself. use the forum for reinforcement, encouragement (we have all been or are going through through the weigh-loss battle) and help.
you're still quite young and have the opportunity to turn yourself into a fit and healthy person for the rest of your life. Don't waste such a wonderful opportunity. You can do it.