Brief Answer: This is due to lack of energy. Detailed Answer: Hi XXXXXXX Thank you so much for this query. I am so sorry to hear abut this weakness and fatigue you have all day. The HCG diet to loss weight works by suppressing your appetite making you not to feel the need to eat. We all know the body needs glucose(food) to function normally and when we do not eat, we would feel weak and tired. This seems to be exactly what you are experiencing now. After eating at night, you would feel a lot better because of the energy intake(glucose). This would again make the body to be able to function normally and alleviate you of most of these symptoms of weakness and tiredness. From the information you have provided, you seem to be too aggressive towards trying to shed off these extra pounds. It is a great idea but how we go about it would determine the end results. If you are too aggressive, you would be unable to follow through because of these side effects. I will suggest that you increase your daily calories intake and don't give yourself too short a deadline to achieve the desired weight. be progressive and gentle with the body so as to continue and achieve the set goals. In addition to diet and HCG, exercises would also be helpful in this process. I hope this addresses your query fully. Thank you so much for patronizing our services and please do feel free to ask for follow up clarifications and information if need be. I wish you the best of health. Dr. Ditah, MD.

---