I am 38 years old and have lost 5 kg over the past 6 months. My clavicles are visible, and I feel very weak and tired. My eyes feel heavy, and I feel extremely sleepy and unable to open them properly. I have had a complete body check up, and all results are normal: thyroid, diabetes, hemoglobin, and infection tests are all normal. The doctor says I have no underlying issues, but I am still losing weight. Please help me understand why this is happening and what I should do.