Hi.
Thanks for your query.
Noted your history that you have Down's syndrome and suffer from frequency of passing motion 5 to 6 times a day, feels inadequate evacuation, has to sit in bathroom for 20 minutes sometimes, lost weight, and there is always gaseous pain in stomach in spite of probiotics that you are taking for the last 3 months.
The most probable causes are intestinal infection that has caused such a problem.
I would advise you the following:
Get stool tested on 3 consecutive days.
Tests the blood for
thyroid and other routine tests for.
Ultrasonography of the abdomen.
This will give an idea.
Get a 5 day course of an antibiotic,
metronidazole, continue probiotics, activated
charcoal.
If this cures your problem well and good.
If not plan for a visit to a Gastroenterologist,
Get
CT scan and
Colonoscopy and biopsy and further treatment .
If all the reports are normal, this is obviously IBS, that is
irritable bowel syndrome and get symptomatic treatment.
Make a list of all the foods and beverages that instigate or enhance the problems and stop them altogether. This may be a trial and error method and may have to stop milk and milk products and so on.
Gluten intolerance can be another reasons and get tested for this too.