Anal intercourse and orgasming, help!

My girlfriend just got back from vacation. We were planning to have intercourse but i did not have any condoms. She has been on the birth control pill YAZ since July 06, 2007. Her period is usually do on the 28th. To make it clear we had anal intercourse on the 25th. I felt as if i was about to orgasm so i pulled out and when i did only a little orgasm came out, and was no where near her vaginal entrance. However i did get scared because she felt a little wet, but it did not look like my orgasm, it was clear, and we figured it was just from her vagina cause fluid from her vagina often leaks down into her anus. We had anal intercourse with her on her back and just to make sure we made sure to clean her vagina and anus off whipping from the top of the vagina down, and getting a new wipe each time. We then had her lay on her back for about an hour, just inc ase i did orgasm inside of her, laying on her back i assumed would help it to leak out and not have any fear of it leaking into her vagina.

I was just wondering how long it usually takes birth control to become effective. I was hoping maybe it was somewhat effective because it has almost been a month, she is almost on her sugar pills now, but still we did not have vaginal intercourse. Can someone please calm my nerves.

She says we have nothing to worry about and i'm glad she is so calm, and faithful about it. I don't want to show her how scared i am because i'm afraid it will stress her out and cause her period to be late do to stress.

Her period is due in on the 28th.

Can somebody please help me =[