Thanks for posting your query.
With the available described details, there appears to high possibility of Acute viral gastroenteritis
Prior history of IBS may be associated with exaggerated risk of flare up of infectious diarrhea.
You should consult with internal medicine specialist/ gastroenterologist and should go for thorough check up.
You should go for complete blood count
, erythrocyte sedimentation rate
imaging, and serum electrolytes, renal function test.
You should take complete antibiotic therapy, antispasmodics, probiotics, antipyretics, if needed.
If itching is present in rash then you should also take anti-allergic medications.
You should maintain your hydration status by taking potassium rich liquids.
Take soft diet
along with yogurt and banana.
Avoid milk and all milk related products.
Dr. Mayank Bhargava