I am 7 weeks post partum and i had sex using withdrawl method on 19th now having brown blood spotting and slight bloating. is this a period?

It could be: The withdrawal method is not usually successful. Is this possibly why you became pregnant? Regardless, it could be a period. See your gynecologist, get a pregnancy test.

Brown blood is not: A period,certainly at 7 weeks postpartum you could have ovulated,especiallif you are not breast feeding.I would suggest you do a pregnancy test if you are concerned about being pregnant.