I'm twenty years old and for the last several months (I think since February or March) my period has been very regular - every 28 days. Before that, I'm not sure, as I wasn't having sex at all, so I didn't need to check the dates or worry about when I was due.
First of all, I did not have unprotected sex - I had a 'fling' with someone I'm not likely to end up in a relationship with. We had sex four times, using a condom each time. I'm pretty much 100% certain of this - although, could there be a small chance that a condom could have split and neither of us noticed? This was around two weeks before my period was due. Surely one of us would have noticed if there had been a problem with a condom.
I haven't had any symptons out of the ordinary, except feeling unusually happy for no reason most of last week, which was a good thing. A few days before I was due, I began to get the normal signs that my period was about to come - slight aching in my breasts and cramps-that-weren't-quite-cramps, and slightly elevated body temperature, which I'm still getting. However, my period was due yesterday. I haven't been late in months, and I'm worrying myself silly that I'm pregnant - which probably isn't helping, from what I've heard about stress delaying periods even more.
I'm aware that this is probably a ridiculous question and that I'm worrying about nothing, but I'm so frightened. I just need some reassurance. Please help?