To start any drug, a doctor must have sufficient reason to do so, and the drug should not be more harmful than the disease it is being used to treat. Drugs used to treat obesity have a lot of side effect. Hence, they are restricted for those who are morbidly obese. In these people the hazards of being morbidly obese outweigh the hazards of taking the drug.
If you want to lose weight, then common causes of weight gain like overeating, lack of exercise, diabetes, hypothyroidism have to be ruled out in your case. You must then look for other causes. One is water retention due to low serum protein. This along with anemia can cause unexplained weight gain. Adrenal gland problems are the other cause. Cushing’s syndrome should be looked for. The kidney function too should be assessed. Late night snacking and poor sleep too can cause weight gain. Polycystic ovary too causes weight gain, hence has to be ruled out by an ultrasound of abdomen. Certain medications like antidepressants cause weight gain.
If all these causes are ruled out then you can start a diet and exercise program to lose weight. If you want to lose weight, then you must do it the scientific way for long term benefits, healthy glow, and a good physique and body. People who are successful in losing weight and maintaining it are the ones who make lifestyle changes which are acceptable to them, their palate and their working style. To do this you must look for healthier cooking options for meals you love, and slowly cut down on the fat in it so as to not irritate your taste buds much.
It's best to join a nutrition expert and a physical trainer and follow their advice. Incorporating yoga into this regimen takes stress out of this exercise to lose weight. Also the diet should contain more of green leafy vegetables, fruits and protein and less of spaghetti, potato etc. I suggest you eat frequent small meals and stop counting calories. It is best to eat lots of fruits and non-starchy green veggies, go slow on fats, eat carbohydrates in moderation and increase your protein intake (lean cuts, whites of eggs etc). Drink plenty of water and non fattening fluids such as clear soups etc. Look for hidden calories in salads and soups and avoid them (eg: cheese, butter, dressings etc).
Also, you need to exercise regularly. You need to start slow and then build up stamina as the days progress. A combination of aerobic, strength training and stretches works best. Many people find it difficult to fit an exercise regimen into their lives. The best way is to join a gym. If that is not possible, try building exercise into your daily life. If you lead a busy life, then walk to work, or to bus stand etc, climb stairs instead of using lifts, walk while talking on cell phone, or briskly walk to any place you are going to. See how you can change your lifestyle to incorporate exercise. Buddy system also helps. You can find a friend either in neighbourhood or online with similar weight loss targets. Thereafter you can either exercise together, or discuss recipes, exchange notes and generally motivate each other. Hope this helps. Take care!
The medical advice given should not be considered a substitute for medical care provided by a doctor who can examine you. The advice may not be completely correct for you as the doctor cannot examine you and does not know your complete medical history. Hence this reply to your post should only be considered as a guiding line and you must consult your doctor at the earliest for your medical problem.