The most important thing is water water water. Cut out sodas, juice and sugary drinks and drink water. If you don't like plain water there are sugarfree flavors you can add to it. Eat lots of fresh fruit and veggies, and learn portion control and proper portion size. Weight watchers is a good way to learn that stuff, but there are other ways online where you can learn proper portions of foods.
Weight watchers is also great for motivation, but you have to make the decision to make a lifestyle change and stick to it. You sound depressed, counseling or an antidepressant (make sure you get one that does not cause weight gain) might help.
I gained over 80 pounds with my twins in 2004. I had never been overweight until then. I have only lost 30 towards my goal and have 50 more to lose to reach my goal, but let me say you have to be dedicated, I lost 50 pounds and gained 20 back. I went to Curves. That is where I lost the initial 50 pounds and when I stopped going I gained some of the weight back.
I had to stop exercising because of a health issue and hopefully can start back in a few weeks after I recover from surgery I had last week to correct the problem.
Another option which should not be the first choice for you if you have not tried the dieting and exercise is having bariatric surgery. Since you are over 100 pounds overweight it is an option for you to consider, but as with all surgery you should weigh the risks and decide what is better for you.
You should always start with diet and exercise. If money is not a problem, I have had friends who were successful with Jenny Craig and LA Weightloss. These were too expensive for me to try so I went with Weight Watchers.
You are not alone. Remember that.