strange menstrual period after loosing virginity

well my girlfriend and i had sex 2 days ago and we used a condom. yesterday or today she was supposed to begin her period, but she did not have a full normal period it was breif. she is used to a very normal menstrual cycle.
does this mean she might be pregnant ?
are there any ways we could know if she is pregnant this soon>?
is this normal ?
should we go see a doctor ?

Yes, there is a very high likely hood that she is pregnant. Usually when there is light blood instead of the full length period this is just the implantation process taking place i which the egg and sperm are digging into the lining of the uterus........got to a doctor ASAP!!

My sister had the same problem after she came back from her honeymoon. She was very regular before and still a virgin. Later, she got the news that her and her husband were going to have a baby. She was pregnant with my niece.

YUP SHE MUST BE PREGGO...GO C A DOCTOR