Ok so on Sunday June 23 2013 at around 1:30 me and my gf were having unprotected anal sex and after a few minutes i felt semen coming so as i was taking my penis out of her i ejaculated a little in her and the rest was outside... so she said that u just ejaculated in me and she ran to the bathroom and cleaned it by wetting a tissue... she came outside and told me that the semen slide toward the opening of the vagina..it didn't go in but was on the outside... we searched a lot online and found out that still there are possibility to get pregnant... we both were scared and the next day June 24 2013 at around 11 a.m we went to Rite Aid and bought the Plan B One-Step pill which is only one pill to take... and yeah her periods started on Wednesday June 19 and it ended the day we had sex which is Sunday June 23... so while sex she was on her periods... even after taking the pill we both are still not full satisfied and we both dont want bad news... i really dont want her to be pregnant and know its all my fault that i should have used a condom... my question is that does plan b one step pill work even if your on periods... like i said it was her last day and we still had it while she was on it... so will the pill work ? will it stop her from being pregnant..please help me.. we cant sleep at night... and yeah im 17 and shes 19... please help me... will the pill work? and i also heard if you didnt eat anythin before and take the pill its fine... and when she took it she didnt eat anythin before that so please let me know... will it work? i dont want her to be pregnant and she doesnt want that either... please