Hello, from the history you have given, well you did not mention about your last menustrual period. Since you also have taken the emergency contraceptive pill at the right time, the chances of pregnancy are very less.If the semen is present on your undergarments, sometimes, yes there is chance of sperms penetrating inside the vagina, but since you have used a contraceptive method, I would suggest you to waite till expected menustral date for your periods to arrive. Hope i was helpful to you.