I took plan b within 24 hours of sex, and a week later, i have slight spotting. is this normal, and my period? and from the pill? or from pregnancy?

Possibly: Taking Plan B can oftentimes cause "withdrawal bleeding" or even throw off your usual cycle. This is very common. If you took plan B within 24 hours of sexual intercourse, as you stated, it is highly unlikely that you would be pregnant. Best wishes.

Pregnant: You are probably not pregnant. The spotting could be your period or could be the effect of planB