How can i stop felling psychologically sick?

well basically i have a kind of phobia about vomiting. Its been about a month since i have started to constintly feeling sick, the feeling does not just go away, its affecting my sleep and me being able to enjoy myself when i go out during the day. I dont know what to do as i feel that i would just throw up! PLEASE help me and give me tips on what to do to make it stop. thanx