For me SAD was the initial diagnosis of my problems. It may be seasonal, BUT it may be more. Always consult your Dr. and let him know how you are feeling. It was more than just SAD for me, the anxiety attacks came after that, then the constant achiness of muscle pain then the continual struggle of depression.
Here’s a link to a site I like its for Depression and Anxiety. Since I had both together and alot of these symptoms so I chose this link!
Here’s a link to The Mayo Clinics post on Seasonal Affective Disorder check it out!