I suggest you go b iou y a home pregnancy test. You can test as early as the third day after e'er. There is a test available that can be done the day after. People are different. One night of no protection and two days after my period ended . I became pregnant on my wedding night. Best bet, take the test then see a doctor.
Normally the last day of your period you would be safe and could figure you are not pregnant. You already ovulated because you said you had your period, right? The next time you will ovulate will be at least 14 to say (to give yourself enough time) 20 days from now. I would suggest you get on the birth control pill or use some method to prevent pregnancy. However, if your time is right for your last period and intercourse, you are safe this time. Hope this has helped you. Take care.