Hi there, I have understood your concern and I will suggest you the best possible treatment options.
First of all do not panic.
If you have stopped taking birth control pills and are having unprotected sex activity, this might cause you to get pregnant.
Secondly, the brown discharge that you have mentioned can be due to some kind of
hormonal changes or due to slight bleeding from cervix due to
cervical polyp or erosion.
I will suggest you the following-
If you are planning to get pregnant then wait for the expected date of the cycle. If you happen to cross your dates, then please get morning's first sample of urine tested for
pregnancy. In case you have any doubts, blood
beta HCG test and USG will be of help.
If you don't want to get pregnant, then you can take emergency
contraceptive pills within 72 hours of unprotected sex activity. This helps to prevent pregnancy in most of the cases.
Please get gynecological examination done including per speculum and per vaginal examination to rule out cervical erosion or cervical polyp.
I hope this helps you.
Thanks.
Dr. Purushottam Neurgaonkar