A guy that is worried....

Hi, I recently had sex with a friend of mine about 2 weeks ago. She is an independent person, intelligent and 36 yrs. old. I was intoxicated and she said that we had sex. Now, I do remember some oral things going on and I remember being on top of her fingering her. But I do not remember any sex. Thats not to say that it did not happen. Anyways, she says she is on the pill and not to worry about anything. And she gets pissed when I ask her about it and I do ask her quite alot. I am 38 yrs old and worrying like an 18 yr old. She had just come off her period when this took place. She says her next one is due on the 23 rd of January. That seems like light years away. She also says that she dont think she can get pregnant because when she was younger she had sex with boyfriends with no protection whatsoever. I was drunk, but I swear I should remember having sex... But am I worrying over nothing???