missing a pill

i am worried and confused coz i missed a pill. i had my period on the 20th of december. and i started to take my yasmin pill on the 24th(saturday) although i still have some spots of blood. what bothers me is i had sex with my bf on the 26th(monday) and i miss a pill i am not sure if i miss the 25(sunday) or the 26(monday) pill but i am quiet sure that i took a pill the day we had sex. if i missed the 25(sunday) and had sex 26(monday) and by mistake i took the 25(sunday) pills on the 26(monday) is there any problem? i noticed that i am missing one pill is on the 27(tuesday) so i took 26(monday) and 27(tueday) pills at the same time. is there any chance that i will get pregnant because of this. but i check in my calendar my ovulation will be on the 31st december or 1st january. and i am on a low fertility stage on the 27th(tuesda). please i really need help