Hi. I Am 24. I Had A Protected Sex With

Hi. I am 24. I had a protected sex with my bf on 6th december. It was our first time and we didnt have intercourse. He tried to but failed. And also he used condom. I had my three periods after that on time. But i missed my fourth period. I was supposed to have my period on 23rd march. I consulted doctor. She asked me to take martinor tablets thrice a day for five days. Yesterday i completed my course. But i am concerned cuz i dont want to be pregnant. Is there any chance of getting pregnant?