In such a case, you must had been exhausted since before you received the Shiatsu treatment. Your body kept be strained not to show your fatigueness on the surface but became relaxed quickly by the Shiatsu treatment at one session, then you might feel the strenth of the body has gone and washed out. However, if you keep to have Shiatsu treatment for more several times, your hiden exhaution will be cleaned away and you will not have such powerless feeling after the treatment. So, you don't have to worry about it.