Thanks for query.
As you are having hypothyroid ,constipation
But in your case urge for going motion and off an attack of diarrhea
, it shows that you might be having chronic intestinal infection like chronic amoebiasis
Go for tablet Ofloxacilin,Tinidazole combination for 3 days under guidance of your doctor
Take plenty of water,more fiber containing diet,fruit juices,papita,banana.
Ok and bye.