Before developing a diabetic coma, you'll usually experience signs and symptoms of high blood sugar or low blood sugar. High blood sugar (hyperglycemia) If your blood sugar level is too high, you may experience: *.Increased thirst *.Frequent urination *.Fatigue *.Nausea and vomiting *.Shortness of breath *.Stomach pain *.Fruity breath odor *.A very dry mouth *.A rapid heartbeat Low blood sugar (hypoglycemia) Signs and symptoms of a low blood sugar level may include: *.Shakiness or nervousness *.Anxiety *.Fatigue *.Weakness *.Sweating *.Hunger *.Nausea *.Dizziness or light- headedness *.Difficulty speaking *.Confusion Some people, especially those who've had diabetes for a long time, develop a condition known as hypoglycemia unawareness and won't have the warning signs that signal a drop in blood sugar. If you experience any symptoms of high or low blood sugar, test your blood sugar and follow your diabetes treatment plan based on the test results.