Yes, it is completely normal to experience morning sickness and nausea at 3 weeks pregnant. While these symptoms are commonly associated with the first trimester, they can occur earlier for some women. Morning sickness is believed to be caused by hormonal changes in the body, particularly an increase in pregnancy hormones like human chorionic gonadotropin (hCG) and estrogen. These hormonal fluctuations can lead to feelings of queasiness, vomiting, and aversion to certain foods or smells. It is important to note that every woman's pregnancy journey is unique, so the timing and severity of symptoms may vary. If you are concerned about your symptoms or if they become severe enough to interfere with your daily life, it is always a good idea to consult with your healthcare provider for further guidance and support. They can provide personalized advice and recommend strategies or medications that may help alleviate your discomfort.