Headaches are your body's way of saying it is not happy, or it is psychological and it is convincing you to give up.
To lose weight, you have to want to lose weight...And I am not talking about wanting to be a differnt size, or wear a bathing suit want...You have to want to make a life stye choice or else you will continue to go on and off diets all your life without any results. You mentioned you have tried many diets...Bingo...Problem right there. The simple fact that you have tried so many shows that you were not willing to make a positive lifestyle change...You were only looking for short term results. Now is as good as any to make this happen for you!!!
First things first....Be prepared to make a full lifestyle change. Yes, full. If u do not, you will not be successful. As well, do not try any fad diet such as atkins, becuase the moment you eat any carbohydrate, your body will store it as fat, and u will be right where you started. You need to eat 5-6 small, well balanced (protein, carbs, fats) meals every day. Your emphasis should be on protein, as protein feeds your muscles, and muscles burn fat. As well, since muscles burn fat, you need to increase your muscle mass (to increase your body's capability of burnign calories/fat)...So start exercising! Lifting weights 3 times a week will be ideal for starters. To shed the pounds, you will need to do cardio exercisise...As much as possible.
If you are really dedicated and determined to lose the weight...4-7 times a week of 30 minutes of cardio should be good. Cardio as in brisk walk, jog, bike, rollerblade (or tread mill, elipticle machine at a gym). Cardio is best done in the morning before breakfast, but if u have a busy schedule, just fit it in somewhere, regardless what time of day. While at work, or wherever, park the car at the end of the parkinglot, and walk in, or take the stairs instead of elevators. Walk to the store, opposed to drive if it is close. Do anything you can to burn calories. Schedule time into your daily schedule as if u had a meeting or appointment, and use that time to exercise somehow. Make it a comittment....A habit. Once you start, and keep it up for a couple of weeks, headaches will probably be gone, and you will feel great!
But as I mentioned before, your nutrition will also be key...No more take out for a while, eat whole grains, veggies, eat fruit in moderation because fruit is very high in sugar (which can be stored as fat). Nuts, seeds are good. But you need to increase the protein. Eat grilled or bbqed chicken breasts...No skin. Eat egg whites, tuna, fish, turkey. Stay away from bagles, and huge portions of pasta (a cup is usually all that should be served). And for the next while, limit sugary stuff...Do not eliminate, but limit.
I work in the health and fitness industry, and I am tired of hearing "i cant lose the weight"...It is more like "i dont want to". Everyone is looking for a mericle pill or diet...No such thing. The weight did not go on over night, and therefore it will not come off over night....It takes time. Diet and exercise are the only real way of losing weight, and keeping it off.
Good luck!!!!!!