I am taking norethisterone and have been for about 2 weeks. today i had a bit of bleeding even though i didn't stop taking it. is this normal?

Yes: Yes, irregular bleeding is expected for the first several months of therapy with a progestin-only birth control pill. It can be quite frequent in some women but generally slows down after 3 - 6 months. After 6 - 12 months of therapy or sometimes sooner, menstruation can stop altogether with regular use, and this is not unhealthy or unsafe.