Welcome to HCM
We understand your concerns
I went through your problem description. Stomack cramp, back pain
etc could arise if your stomach is empty and your abdominal muscles are weak. Then most probably we faint. Taking a glass water might probably relieve the symptoms. I hope you had that because you were tired and empty stomach. This is one of the possible explanations.
But there are so many others. You should consult a physician to get a proper diagnosis. Please do not indulge in self diagnosis.
Hope this clears your doubts. Available for further clarifications.