When you feel like vomiting

I think I'm going to vomit. ("My stomach is upset. I think I'm going to vomit.")    

I think I'm going to throw up. ("I have eaten too much. I think I'm going to throw up.")    

I think I'm going to barf. ("I feel dizzy. I think I'm going to barf.")    

I feel like throwing up. ("I'm airsick. I feel like throwing up. Ask a flight attendant to give me a barf bag.")    

I feel nauseous. ("I'm seasick. I feel nauseous.")    

I feel sick to my stomach ("I can't eat. I feel sick to my stomach.")    

I'm sick to my stomach. ("I don't feel well. I'm sick to my stomach.")