Watch for danger signs If your blood sugar level is very high, especially if you are ill, you may experience symptoms like extreme thirst, passing a lot of urine, headaches and lethargy. If this happens, seek immediate medical attention. Occasionally, your blood sugar level may be too low, especially if there is a long gap between your meals. This causes symptoms such as cold sweats, tremors, light-headedness, drowsiness and confusion. Check your glucose levels if you have a glucometer on hand. If the reading is below 4 millimoles per litre, drink half a cup of fruit juice or soft drink, or three teaspoons of sugar, or three pieces of sweets, to quickly normalise the blood sugar level. If you do not feel better, make sure you seek immediate medical attention.