Sir, I had my periods end on on 4th of may and on 6th may I had un protective sex and took I pill on the next day now after 6 days that is 13 th may I have brownish flow am I pregnant... please reply soon

Too early to tell.
You will need to wait for your next cycle.

Sir is there any chance that I am pregnant as I have already taken I pills before that monthly after having sex and getting regular periods

There is always a chance of pregnancy with sex either protected or not.

there is always a chance of pregnancy with sex either protected or not.
So when to check for the pregnancy and confirm it. Do I have any way of stopping it

Actually its water-brownish flow