This could be a common sleep disorder such as obstructive sleep apnea or some other form or degree of sleep disordered breathing.  Many people have different degrees of airway obstruction which are described in different terms such as upper airway resistance syndrome, primary snoring, and obstructive sleep apnea hypopnea syndrome to name a few. You shuold ask a witness to your sleep if you snore.  Even very mild, intermittent snoring can cause significantsleep distrubances. Any degree of snoring is airway obstruction and can be quite variable, even absent at times, during the coarse of a given sleep period in the same night.  There are very affordable methods of screening for this disorder, although the more mild spectrum of airway obstruction is more easily diagnosed with a full polysomnography exam or sleep study.   You should talk about this possiblity with your doctor or a sleep specialist and possibly undergo a simple screening test, especially if you have a history of snoring to any degree.  You don't have to be overweight to have this condition, which is a very common misperception regarding sleep disordered breathing.  There are several other factors that may cause the problem or combine to cause airway obstruction during sleep. When this condition is present, especially to a mild degree it may be undetected by an inexperienced staff, poor collection of sleep data, or certain circumstances present during the evaluation in the sleep laboratory.  If you undergo a sleep study, it should be performed by qualified and experienced medical staff, at an accredited sleep center.  I have seen patients with these same symptoms and in their cases, sleep disordered breathing was the culprit.-Good luck!