Is it possible?

There is no "safe" time in a woman's cycle to have sex, so anytime ou have unprotected sex, you are at risk for pregnancy. A woman does not become pregnancy instantly; it actually takes 10-14 days from the moment of ovulation to implantation of the fertilized egg. If you are worried about pregnancy, you may choose to use emergency contraception up to 120 hours after unprotected sex.

If you would like to know more, I've included the long answer with a lot of detail. Many women have a regular 28-day cycles, which means they ovulate around the middle of their cycle ("day 14" is the typical mid-range day of ovulation for 28-day cycle, and you can add 2-3 days to either side of this date as possibilities for fertility, so your most fertile times would be between days "day 11" through "day 17"). Many more women are not perfect 28-day cycles, and there are so many possibilities that a woman can ovulate early or late in her cycle.

Please know, however, that "day 1" is the first day of your period, so if your period lasted 5 days, then you had sex a few days after your period ended on "day 8" of your cycle...sperm can live inside a woman's body (at her most fertile time) for up to 3-5 days...which puts the possibility of conception at "day 13"...during your fertile window.

This is the long explanation why there is no safe time to have sex, but the likelihood of a woman conceiving with one unprotected sexual encounter is only 20% for that one cycle (each time you have unprotected sex, this number increases).

I'm not sure if you wanted all of this information or not, but please let me know if you have any other questions.