Thanks for query.
It seems that you might have chronic dysentery
giving rise to this problem.
What I would suggest you to go for one anti amoebic dysentery medicine course.
After few days you will get result.
Another possibility is this problem might be due to gastro-colic
reflex giving this sensation after taking any thing by mouth.
In this condition once you decide that even you want to go for toilet, you stop that feeling forcibly.
By doing this gradually feeling of going for toilet will stop.
Ok and bye.