Can i get pregnant on 5th day of period? i have a 31 day monthly cycle, should i take plan b?

Yes, possible: Though the risk of pregnancy on day #5 is lower than at day #14 (for example) pregnancies CAN occur on this day especially if you ovulated early. I'm not a Gynecologist, but I recall a chart of the % of times a pregnancy can occur at different days in the cycle during my training. None of the days are at 0%. Now, taking "Plan B" is a complicated decision. Talk to your doctor about pros and cons.

Highly unlikely: If your menstrual cycle is regular, and periods are predictable, then it is highly unlikely that you can get pregnant if u have sex on 5th day of your period, so Plan B should not be necessary. However, if you are very concerned about unintended pregnancy, then use effective contraception consistently, which is more cost-effective than periodically using emergency contraceptives like Plan B.

Not likely: improbable and do not take plan B- it will make you bleed much harder and make your cycle uncertain. You rarely, if ever, can get pregnant on you regular cycle.

Prego/period: Highly unlikely to get pregnant during period, so you should stop worrying about that. You should however, get regular birth control now that you are sexually active.

Not likely: However, not all bleeding is a period, so if your cycles are irregular at all I would take plan B. I know for years women have been told by men and their friends that period sex is safe as far as pregnancy goes. Not always. Probably time to see your doc for some birth control

Not likely, but...: It's not likely, as ovulation is probably several days away. It wouldn't hurt to take it, however, just to make sure, it sounds like you need to think about birth control.