I'm on BC pills right now and have a tubal scheduled for Dec. so, no, I don't think it's a sin.
Before we moved, I was taking the kids to a great playgroup and about half of the members of the playgroup were active Catholics. (I was raised Catholic myself, but don't attend Mass much.) At any rate, during our usual playgroup meeting one day, we got on the subject of birth control. Despite the Church's views/teachings, every Catholic in our group was either using pills or had had a tubal/husband had a vasectomy. The only person anyone in our group gave a hard time was the one woman who said she mentioned using birth control as one of her sins during confessional and had to do a penance each time. Several other members teased her for actually telling the priest during confession -- no one else considered it a real sin and, therefore, weren't willing/able to confess it!
As for "Family Planning" contraception, I have several cousins conceived using that method of birth control.