Hi, The symptoms you are experiencing, including abdominal bloating, nausea, fatigue, and an ulcer in the mouth, could be caused by several different conditions. One possibility is that you have developed a stomach or intestinal infection, such as gastroenteritis or food poisoning. These conditions can cause bloating, nausea, and diarrhea, and are often accompanied by fatigue and general feelings of malaise. They are typically caused by a bacterial or viral infection and can be treated with rest, hydration, and over-the-counter medications to manage symptoms. Another possibility is that you have developed an ulcer in your stomach or small intestine. Ulcers can cause abdominal pain and bloating, as well as nausea and vomiting. They are typically caused by an imbalance of stomach acid and can be treated with medication to reduce acid production and promote the healing of the ulcer. It is also possible that your symptoms are related to hormonal changes or imbalances, such as those that can occur during menstruation. Some women experience bloating, nausea, and other gastrointestinal symptoms in the days leading up to their period. Hormonal imbalances can also cause fatigue and other symptoms. To determine the underlying cause of your symptoms, it is recommended that you consult with a healthcare professional. They can perform a physical exam and order any necessary tests, such as blood work or imaging studies, to help diagnose the problem. Based on the diagnosis, they can then recommend appropriate treatment options to alleviate your symptoms and promote healing. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Priyanka, General & Family Physician