These vary greatly depending on the type and severity of the disorder. If you have a sleep disorder, you may experience any of the following symptoms: Difficulty falling or staying asleep Frequent awakening at night Excessive sleepiness during the day Falling asleep suddenly at inappropriate times, such as during work or while driving Difficulty thinking, remembering things, or concentrating on tasks Delayed response to stimuli Emotional instability Sleep deprivation Irregular sleep-wake cycle Breathing disturbances during sleep, such as snoring, gasping or choking Abnormal movements or experiences during sleep, such as seizures or frequent nightmares Speak to a doctor if you feel tired even though you think you're getting enough sleep, or if your sleep problems are affecting your quality of life.