I have a 6-7 day period (irregular) sometimes heavy & light with flow i had unprotected sex on the 31st & 7th on the 5th istarted bleeding em i preg.

Possibly: Irregular menstrual periods will always affect your chances of getting pregnant. You can also have vaginal bleeding in the first 1-2 months of pregnancy and think it is your period. I recommend a home pregnancy test and pelvic exam with your doctor this week.

Postcoital bleeding: Bleeding irregularities are rarely useful as indicators of pregnancy. A pregnancy test is the only way of knowing one way or the other.

Pregnancy possible: Pregnancy is always on the list of possibilities when a woman has abnormal uterine bleeding or cycles. You may be having anovulatory cycles (cycle without producing an egg from the ovary). If a urine pregnancy test is negative, i would recommend evaluation by your gynecologist, and treatment will depend on the cause of the abnormal bleeding and your current short-term pregnancy goals.