It doesn't sound like it. Ovulation comes two weeks before the period, not a matter of hours before the period, and the egg does not last more than 36 hours, so there would have been no egg available to get fertilized. Check for STDs and then try not to do anything unprotected again until you're ready to get pregnant.
While I agree it is unlikely, ANY time you have unprotected sex during your cycle is a risk for pregnancy. The very rare occurrence of two eggs released and at different times can happen. Albeit, as I said, rare. Many babies are conceived from the calendar method of birth control because of this as well as misjudging what is actually going on with their body. Would I be overly worried? No. It's highly unlikely given the timing. Definitely concur with AnnieBrooke that it's important to protect yourself from STD's as well as unplanned pregnancy, so buy your own condoms, get on the pill, etc. Good luck