Girlfriends Pill

So after talking to my lady, She is all worried, as one of her friends draped one of her penicillin pills into my fiance's drink, as she was walking by. Her friend didn't seem to think it be important to tell about this miss hap. They yet to of found it, in the mean time My Fiance drank the glass of juice, pills and all. Her friend now tells her a week later, that she thinks her pills had fallen into her juice.
Thank God Nicole isn't as allergic to Piniciline as I am, or she would be dead. But is now slightly concerned as she is on the pill, and we don't use any other type of birth control. Her thought is that if it's meant to be, we will become pregnant. But Really what are the chances of something like this happening? And come to find out, I think that her room mate is actually doing this on purpose. As her other room mate said it's not the first time this MONTH that she has done this. I am ready, and wouldn't mind being a dad, but I would like to think that my boys don't need help from a pill that is being sliped in her drink