The sudden and intense feeling of thirst can be caused by various factors, including:

• Dehydration due to not drinking enough fluids, sweating from exercise or heat, vomiting, or diarrhea.
• Eating salty or spicy foods that increase the body's need for water to balance salt levels.
• High blood sugar (hyperglycemia), which is a symptom of diabetes.
• Certain medications like diuretics, lithium, or antipsychotics that can cause dry mouth or increase fluid loss.
• Medical conditions such as diabetes insipidus, heart, liver, or kidney problems, or infections like sepsis.
• Dry mouth from reduced saliva, sometimes due to smoking, anxiety, or health issues.

This thirst is your body's signal to replace lost fluids or address an internal imbalance. If the thirst is very strong, persistent, or accompanied by other symptoms like frequent urination, fatigue, or blurred vision, it is advisable to consult a healthcare provider for proper diagnosis and treatment.