Hi. Thanks for your query. Noted the history and understood your concerns. This is very rare phenomenon of having drained energy, fatigue and feeling exhausted after passing bowel movement. The most probable causes can be as follows: Proctocolitis that can drain the electrolytes from intestines so that you are getting such symptoms. Vaso-vagal preponderance can be another reason getting instigated by bowel movement. Associated other medical problems can also be reasons. Hence I would advise you the following in such a situation;: Tests of stool. Tests of blood for CBC, electrolytes, liver, thyroid and kidney functions. Colonoscopy is mandatory. Clinical evaluation by a General Surgeon can help further get a proper diagnosis and get a plan of proper management. If the electrolytes are reduced you may need to take electrolyte solution when in attack. Further management will be as per the findings of the tests and clinical examination.