Symptoms. The symptoms of a sleep disorder are varied and will depend on the specific type as well as the underlying causes. However, those suffering from a sleep disorder may feel excessively tired during the day whilst having difficulty falling asleep at night. Abnormal or disrupted breathing is also common and can manifest through loud snoring and choking noises. Those affected by sleep disorders may feel restless or experience increased mental activity and physical movements during the night. Lack of restful sleep can also make a person irritable, anxious, or even depressed. Struggling with concentration and failing to be able to focus are common. Weight gain, bed wetting, sleep walking, nightmares, and teeth grinding are also symptomatic of a sleep disorder.