Had unprotected sex 2days after period ended(he claims to not finish) took planb 24hrs later. now (6days later) red streaks & light spotting. what?

Expected: Plan b is a hormone and taking it increases that level of hormone temporarily. When you do that and that level drops back off you often times have spotting or breakthrough bleeding. Plan b is not 100%, though you did take it within 24 hours, which is prefered. Consider checking a pregnancy test 14-21 days after you took the Plan B just to be safe.

Might be Plan B SE.: Emergency contraception symptoms can include spotting or bleeding, changes in menstrual flow or your period may be late or early. Take a home pregnancy test & notify your GYN if your period is 7 or > days late.