If i had unprotected sex on my period, should i still take plan b'?

Not necessary: If you have a regular menstrual cycle, you should not be able to get pregnant during yuur period. If your bleeding is irregular, your 'period' may not actually be a true menstrual cycle, and you may be fertile at that time, though it is still unlikely.

Plan B: The risk of pregnancy during your period is very low. There are cases where pregnancy has occurred with women who have very short cycles and had sex later in their period. Always use protection if you don't want to risk pregnancy.