Hi Kharma,
Well, you have answered your own question in your 1st paragraph...you have tried every diet. Your body has an inner thermostat, it is naturally regulated to burn the food that you eat as energy for all of your bodily functions, to feed your muscles and brain. When you go on a diet, you start to lose weight quickly then you stabilize and it becomes impossible because you lower your thermostat...so you give up.
Then you go on another diet. Same thing except that you need to eat less to lose weight. Then you stabilize again and stop again and the circle continues...your body gets used to eating less and less and functions on a lower metabolism...you have thus reset your thermostat on low.
There are basically 2 ways to kick up that thermostat naturally.
First is to do more. The more you move, exercise, walk, and stay active the higher your thermostat goes...it burns more calories as you move and as a bonus it builds muscle tissue which burns more calories than fat too...even just resting, so the effect lasts beyond the exercise period.
The second is eat better food. Not less.
Eat more healthy protein and less fat (fish & chicken as opposed to fatty meats). More wholegrains and less white. More healthy fats (olive oil and butter as opposed to margarine), no prepackaged, commercial foods that are full of sugars, fats and salt...
Natural and homemade do wonders for your body. Increase your activity level and decrease your sitting time. Get a yoga ball and roll around on it while watching tv, walk around the shopping mall before shopping, do all of the aisles of the grocery store twice before shopping, park at the other end of the parking lot and carry your groceries (if you can) to the car...you do not need 6 hrs in the gym to lose weight but an easy way to kick up your activity level with doing anything special.
Swim. Swim. Swim (your body will love you!).
It is a very long race to dominate your body. It is not a sprint. Take it very slowly, and do NOT diet. Just eat healthy foods, often (3 meals and 2 snacks/day) and double your water intake. Sip ice water, not sodas. No diet soft drinks or foods with fake sugar (your pancreas hates them).
You will see that you will retrain your body and slowly but surely you will lose the weight.
Good luck
Sharon