Hello, thanks for your question. It sounds like there is a possible risk of pregnancy and to prevent that you can take emergency contraception called Plan B. This is best taken as soon as possible and can be taken up to 5 days after the risk and still be effective at preventing a pregnancy. When this is taken you should get a bleed like a period within 21 days no matter when your period is expected. If there is no bleeding like that in three weeks, then a pregnancy test is recommended.
Plan B emergency contraception is available free at youth clinics.  For a listing of youth clinics near you see  http://www.vch.ca/your-health/youth/youth-clinics/  or you can call the the Sex Sense Line  1-800-SEX-SENSE (1-800-739-7367) throughout BC* or 604-731-7803 in the Lower Mainland.
Hope this helps.
Health Nurse