Morning nausea can have multiple causes besides pregnancy. Common reasons include:

• Low blood sugar: Going many hours without eating overnight can cause blood sugar to drop, leading to nausea, dizziness, and weakness. Skipping breakfast can worsen this feeling.
• Acid reflux: Stomach acid flowing back into the esophagus, especially when lying down overnight, can cause nausea and a sour taste in the morning.
• Sleep issues: Poor or disrupted sleep affects the body's neuroendocrine response and can trigger nausea.
• Sinus congestion or postnasal drip: Pressure on the inner ear or mucus drainage into the throat can cause nausea.
• Anxiety or stress: Emotional stress often manifests with nausea and an upset stomach in the morning.
• Dehydration or hangover: Not drinking enough water or alcohol consumption the night before can irritate the stomach and cause nausea.
• Other causes can include infections, food poisoning, gastroparesis, ulcers, constipation, or medication side effects.

Eating a balanced meal before bed, staying hydrated, managing stress, and avoiding triggers like alcohol or acidic foods may help reduce morning nausea. If nausea persists or is severe, it's important to seek medical advice to identify any underlying conditions.