Intercourse is considered to be the least effective method of contraception. Therefore, in my opinion, it will be necessary to consult a doctor, because emergency contraception is available in Poland on prescription. The chance of pregnancy as a result of intercourse during the first day of menstruation is small, but not zero, because sperm can survive in the genital tract of a woman for several days and if ovulation occurs during this time, fertilization can also occur. If it is not possible to visit stationary, I encourage you to take advantage of the teleadvice offered, m.in. by the Gdziepolek.pl portal: https://www.gdziepolek.pl/telekonsultacja You can use the help of the foundation: https://fundacjajeszcze.com.pl/szukam-pomocy/pilna-pomoc/ It happens that in the preejaculate (which is a colorless secretion), there are trace amounts of sperm, which after getting into the egg can fertilize it. Therefore, we can never be sure that fertilization will not occur. The Perl index for this method of preventing pregnancy is between 4 and 28, which means that within a year out of 100 couples using intercourse from 4 to 28 will become pregnant I encourage you to read the article: https://www.gdziepolek.pl/artykuly/tabletka-po-czyli-antykoncepcja-awaryjna.