hi doc, i have missed 2 pills from my althea birth control pills on the 3rd week (15th and 16th), since i remembered to take 2 pills the moment iremmbered it, i took 2 pill rihgt away (15th and 16th), the 17th pill and 18th were taken the next day. i dont know if that will work, and had unprotected sex after 2 days. what should i do not to get pregnant?