When do you get morning sickness?

When did you start getting morning sickness? I just want to see when everybody had morning sickness and then found out they were pregnant. I've been having morning sickness for a week now it's off and on all day but I haven't thrown up, it's just the feeling of throwing up. I'm not sure if this is even morning sickness because I'm not suppose to get my period for another 2-1/2 weeks now ..