HI.
Thanks for your history and query.
Having loss of sex-life in addition to the problems you have explained is a serious matter .
The most probable causes are :
Irritable Bowel Syndrome.
Abdominal tuberculosis. Nonspecific
Gastroenteritis.
I would advise the following investigations and treatment in a such a case:
Investigations:
*Routine blood investigations like Complete blood picture, blood sugar, urea, creatinine, liver function tests,
thyroid function tests.
*Urine -routine and microscopy
*Stool: routine, microscopy, occult blood, culture and sensitivity.
*
Ultrasonography of abdomen, and CT scan of the abdomen.
X-ray of the chest to see for TB or other problems.
*Colonoscopy
All these investigations should be within normal limits for one to say you have IBS.
Once a proper diagnosis is made , it will be easy to get a proper treatment, that will cure your problem, improve your health and sex-life.