Nausea could be down to diet, lack of sleep, or anxiety. Boy Anupong/Getty Images Nausea is sometimes a symptom of pregnancy, b ut people feel sick in the morning for many reasons. For instance, it could be down to diet, lack of sleep, or anxiety. Mild nausea can be treated with small changes, but if the problem persists, you should see a doctor. If you're a woman, feeling sick in the morning is known as one of the first signs you're pregnant. But it's not the only reason you might feel queasy when you wake up. "When we hear about morning sickness, most people's first thought is pregnancy," said Dr. Janice Johnston, the chief medical officer and cofounder of healthcare provider Redirect Health. "This is because morning sickness is a very common side effect in pregnancy, specifically in the first trimester, affecting about 7 in 10 pregnant women." The reason morning sickness is so common is due to a particular hormone called human chorionic gonadotrop...