Female 18yrs. My question is about pregnancy.

Patient: Female 18yrs.My question is about pregnancy.my last period was 23rd march and after 20days on 14th april I did unprotected sex with my hubby, he pulled his penis out shortly before getting discharged, but i am still suspecting that i am pregnant as my periods have not been arrived yet.please advise what should i do to bring periods, we dont want baby at this stage.