male 55, I have lost approximately 50 pounds since 10/14. I swim at least 4 days a week for at least 45 minutes, i do approximately 500 crunches of different varieties in the corner of the pool to keep stress from my back. I just get tired quickly near the end of the day, normal day 5:30 am til about 8:30-9 PM then I just have to go to bed, never had this symptom before. I eat a high protein low carb diet which has helped with the weight loss, Why am I suddenly so tired all the time?