Well... while our far more knowledgeable female members dont manifest themselves, i will risk an opinion. Note that im a guy also, so my opinion may be pure crap.
Anyway... getting pregnant is not one of the easiest things. Unless you be VERY unlucky. Of course it can happen, but i think you should not worry too much until you get some greater sign of pregnancy.
Also, if she actually were pregnant, you will have plenty of time to worry about it. So, enjoy while you still can have hope of her not being pregnant.
And good luck! Im sure you will need it... :thumbsup: