Can I get pregnant on birth control? If I had started taking birth control a little over a month ago and had unprotected sex and believe that I had semen in me after, will I get pregnant? If so, do you advise to take the Plan B pill?

If. If used correctly, the birth control pill is 99% effective 7 days after you start taking it. It's recommended that you use a back-up method the first week you are on it, but after that, you are protected against pregnancy. The pill becomes less effective if not used properly such as skipping pills or when taking certain medications like antibiotics while on the pill. In those instances, you will want to use a back-up method like the condom. Below is a link which gives more information on the pill. If you have unprotected sex and have not been taking the pill every day, instead of plan b, many pill packs come with instructions on what to do.