Congratulations on the weight loss and exercise program. First try out the Healthy Body Calculator® and find your healthy body weight. Is 145 pounds a realistic weight goal? Your body fat (same as BMI) seems healthy for a woman so your body weight at 150 is probably proportionate to your height. Your exercise program would provide you with increased energy so I would recommend continuing your routine. Have you considered adding weight training?
The symptoms you describe when forgetting to take phentermine are not surprising since one of the drug’s side effects is sleeplessness. So, when you forget to take a pill, your body remembers to sleep more.
Generally, when people quit taking phentermine, fenfluramine or a combination of the two, weight gain occurs according to current research. I would not suggest you rely on phentermine for a long-term solution to your weight as weight loss seems to plateau after 6 months. Long-term weight loss requires lifestyle changes that include reduced food intake, exercise and food intake diaries. Research has shown that a 10 – 15% reduction in weight, significantly decreases obesity-related illness. Is 145 pounds a realistic goal for you?