I have been taking phentermine since 5-8-15 and I honestly don't think I have lost any weight. I have went on a 1200 calorie diet also. And have been drinking nothing but water. Any suggestions? Has anyone had this pill not work for them? I am taking the 37.5 dosage. I am 22 4"11 and weighed 155.6lbs. I haven't weighed myself since bc I don't have a scale...