Hi Constant fatigue and weakness may be seen in a number of diseases. Alternatively mood swings can happen with the stress related to modern lifestyle habits. The cause of the same needs to be investigated and can be corrected with proper professional help. Please visit a General Physician or you can consult me directly via practo for further evaluation and ,management. In case of further doubts, please feel free to write back to me. Regards Dr Prashik Meshram