Ive been taking Phentermine ( Adapex ) for 2 weeks. The first week I lost 12lbs mostly in the first 3 days i thought i had found the merical pill, but towards the end of the week and the entire second week i havnt lost anything. Actually i gained 4lbs back. Im on a 500 calorie diet im drinking lots of water and running everyday... Im 17 5'5 was 216lbs weigh 205 now... Im a swimmer, water polo player and dancer.. Why isnt it working anymore?