Condoms are typically over 95% effective. The main times when they fail are when the condom slips off, splits or rips. I'm sure you would have noticed if this was the case. Unless this happens, the efficacity of condoms is almost as good as the pill itself. Also, you'd have to be on the fertile period of your menstrual cycle in order to conceive. I wouldn't worry too much, although I don't think taking two pills in one day is really a great idea...