Check for CBC test, thyroid test for weakness

Your pattern—sometimes normal stool and sometimes loose/mushy stool for around 1.5 years, together with anxiety and sudden panic episodes during sleep—can occur with an IBS/gut–brain interaction, particularly when bowel symptoms fluctuate with stress. IBS commonly causes alternating changes in stool consistency, and anxiety itself can produce gastrointestinal symptoms including diarrhoea, abdominal discomfort and sleep disturbance. The leg cramps and fatigue, however, should not automatically be attributed to anxiety or IBS. Episodes of frequent loose stool can contribute to fluid/electrolyte loss, which can make you feel weak or develop cramps. Your description does not by itself suggest that something is wrong with your brain or heart. Night-time panic can feel extremely physical—racing heartbeat, sweating, breathlessness, dizziness and a sudden feeling of danger—but panic attacks themselves are generally not dangerous.

Please take general physician consultant

Waking suddenly with panic, leg cramps, and loose stools for over a year points more toward your body's stress response than a heart or brain problem. This still needs to be confirmed by a doctor, not assumed on your own.