I read up on morning sickness.

I've started reading a book on pregnancy and it says that morning sickness starts around the 8th week of pregnancy. Is this true? As I don't know how far along I am yet (waiting for a scan appointment) and I've started vomiting. I'm guessing this puts me in the ball park of around 8 weeks? right? UPDATE: I must be around 6 weeks then 😊 ANOTHER UPDATE: I'm talking vomiting not feeling nauseous