Thanks for posting your query.
Let me explain your query one by one.
You are most likely suffering from acute gastroenteritis
as history of increased usage of washroom suggest.
You should consult with physician / gasto-physician and should go for complete antibiotic course.
You should also avoid mik and all milk products & take antispasmodics and probiotic
for faster recovery.
As you have history of weight gain, you should go for thyroid
Increasing weight may also cause pressure on nerves and may damage cartilages in joints and may be a reason for continuous pain in lower limb.
You should also go for serum uric acid.
Dr. Mayank Bhargava