Is it possible for me to be pregnant 13days after my periods?

It is possible to: It is possible to become pregnant at that time (especially if you have sex of day #13 of a 28 day menstrual cycle). Take a pregnancy test to know.

Please clarify: I am not sure what you are really asking. It seems there may be a disconnect with facts and your feelings. One becomes pregnant with exposure to fresh semen during the five days prior to ovulation. Females ovulate usually just shy of half way through their cycles and sperm deposited in the vagina during intercourse in the days leading up to ovulation are most likely to cause pregnancy.