1436, Yes, it is quite normal to spot/bleed about a week after taking emergency contraception. Plan B is a very high dose birth control pill. When the hormones get out of your system, your uterus will bleed (withdrawal bleeding).
Your period may also not come when you expect it, so don't freak out when that happens.
I hope you are making another plan for birth control. Plan B is not meant to be used as contraception and is only 87% effective. You also need to protect yourself from infections and STDs.
Take care!