Don't know what to say to work. Pregnant?

Hi im 21, Basically I have had 2 weeks off with morning sickness I said it was the flu. But I'm still getting sick and I can't work it's all day and is really bad I've lost 4 kg in 2 weeks. What do I say I'm 9 weeks. I'm also a nanny and I don't think parents would be happy with me leaving there children to be sick evey fue min. I don't know what to say to my agency. Thankyou.