I'm on birth control but I had unprotected sex, took plan b but still no period, am I pregnant???

Number one, you do not ovulate while on the Pill-this is how it works-it prevents ovulation, no egg=no baby no matter how many sperm are present. The only way you can ovulate while on the Pill is if you miss pills. Being a little late on occasion isnt going to reduce effectiveness by that much. I'm not sure what you mean by "the timing with your birth control was off" if you were late a few times-you didnt need Plan b. Plan b is a huge blast of hormones. It is to delay ovulation slightly but if you are on the Pill you dont ovulate anyway. All Plan b does is mess up your cycle and can give you nasty side effects from all the extra hormones on top of the Pills hormones. Plan b is notorious for delaying periods. Keep taking your birth control pills every day and take them on time. "On time" can be an hour either way of your time. If you pick 4 pm, you are on time if you take it between 3 and 5pm. Just keep to your schedule. Start your new pack when it is time whether you got a period or not. Your cycle should be back to normal in a month or two. Next time if you are unsure, have your partner use a condom. Plan b doesnt mix well with the Pill. Plan b is not nearly as effective as regular birth control pills. Everyone seems to think it is this magical substance that totally prevents pregnancy. I'm sure the manufacturer is making millions! Plan b is only about 80% effective compared to 98-99.9% for the Pill when taken consistently and correctly.