You got good answers from both Marte and Ten but I just wanted to put my 2cents in.
A disturbance in your sleep patterns, whether it be lack of sleep or too much sleep, is a symptom of depression.
I'm the same as you Shana. I go for a week or two of very little sleep.....can't fall asleep. Then go a week of a more "normal" pattern. While I'm on my "very little sleep" pattern, I take one or two hour naps to make it through the day which by the way doesn't help with trying to get to bed at a decent time!
Good luck!
doll