That depends on the person and the pregnancy.Some it starts around 9 weeks and last until around 16 weeks.For others it's all through the entire pregnancy.Then there's the lucky ones who never get sick at all. I've had six pregnancies. Two of them I was bed ridden for three months with nausea and vomiting.Three of them I had nothing at all. Number six I had just a little sickness in the morning but it would go away once I ate something. Every pregnancy is different. Good luck.
The pregnancy symptoms vary from one woman to another and their timing is also different. You can start feeling sick immediately or not feel sick at all. However, your case seems serious. If all the symptoms of pregnancy are there, you must consult a doctor. Or take a home pregnancy test to be sure.