Sounds like you have a bad infection going on. The grey stool could be as a result of constipation and this in turn can be as a result of dehydration due to excessive fluid loss. If you have a bad infection you will have a raised temperature . I suspect you may need to see your doctor to go on a course of antibiotics. He may also need to carry out some blood tests. In the interim period drink plenty of water. Don't drink it too quickly but lots of sips over a longer period. :the back pain may be as a result of constipation as may the abdominal pain. However, abdominal pain and rigidity can be an indicator of other more immediate problems . So I would advise you not to wait too long to see a doctor. If it gets worse I would advise a trip to the casualty department. But I still think itsan infection. Bleeding in the tummy usually produces thick tarry black stools called melena. However, no point in taking unnecessary risks with your health.
