Hi there I understand your concern and anxiety... Chances are very less as sexual contact was safe but it can be possible due to failure of contraception due to various reasons... If you miss period go for home pregnancy test if positive consult nearest gynecologists... if negative nothing to worry.
There are least chances of becoming pregnant since there was protected intercourse. If you miss your periods, do a urine pregnancy test to confirm pregnancy. If the result is negative, there is nothing to worry about. If the result is positive then consult a gynecologist for further evaluation and management.
You can also visit my clinic International Fertility Centre located in New Delhi for further evaluation. My clinic offers varied gynecology treatments and services to help you have a successful treatment. You can mail me your contact details so that I can get in touch with you.