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The symptoms can be due to low testosterone, anemia, diabetes, hypothyroidism, or due to kidney or liver problems. Another possibility is sleep disturbances (like sleep apnea, imbalance of rapid eye and non rapid eye movement sleep etc.). You may sleep your customary 7-8 hours and yet feel fatigued. You need sleep studies to rule this out. Other possibilities are chronic fatigue syndrome, depression, low Vit b12, low iron, low calcium, sodium and potassium. Hyperthyroidism too causes increased sweating and tiredness. Postviral fatigue syndrome is another possibility. Persisting EBV infection or mono can also be the cause. A comprehensive investigation is required keeping all the points in mind. Do discuss this with your doctor and get yourself examined.
Obviously, there is something wrong with you or the doctors wouldn't be able to diagnose you. If you don't like your current doctor, apply to a different doctor and keep the existing one in case the current doctor may improve his/her skills.
Maybe a reaction to the meds. Maybe minor strokes.