It's really unlikely but as above, it is possible. Do you track things? Do you know when you ovulate usually? Chances are higher if you ovulate much earlier. If say you ovulated somewhere between say CD9 - CD11, since sperm can live for up to 5 days (some say up to 7 days), then it's possible, depending when your period finished of course. If you ovulate later than this then it's almost impossible. They'd have to live for a week up there at least, and the vast majority of evidence suggests 5 days maximum. Only way to know is to test or wait for your next period