Hello and Welcome to ‘Ask A Doctor’ service. I have reviewed your query and here is my advice. Persistent fatigue may be due to anemia, depression or hypothyroidism or electrolyte imbalance or chronic fatigue syndrome etc. Weight gain may be seen in hypothyroidism or kidney or liver failure with fluid retention or diabetes or metabolic syndrome etc. Until examination is done it is difficult to say what it is. Drink plenty of liquid s , take rest ,do yoga and meditation. Please consult your physician he will examine for hemoglobin, electrolytes, thyroid profile then treat you accordingly. Hope I have answered your query. Let me know if I can assist you further.