Yes, you could get pregnant. If you don't want a pregnancy to occur, you should take Plan B (it's most effective 72 hours after the incident, the sooner the better).

Odds of conceiving vary depending on your cycle. You would have very low odds of conception if the incident happened in the first part of your cycle right after your period (assuming a normal 28-day cycle)--the chance of a pregnancy occuring if this happened by day 5 of your cycle is low to none. You would have higher odds after that, especially the closer you get to ovulation (around day 14 for a normal 28 day cycle). If you're beyond day 14-18 with very regular cycles, odds are you have already ovulated, and you wouldn't get pregnant (unless your ovulation was delayed by stress or illness).