Am on my third week of the BC pills. I take the pill at 10.00pm. I would like to change to 9.00pm for convenience. Will it add my chances for being pregnant. Am on my first pack of 21 pills and currently on my third week. I understand after the 21 pills are over I should wait for seven days before starting a new pack are there chances of being pregnant for having unporetcted sex during those seven days. Please help