Tasha I seriously thought I had something wrong with me the past 2days, I was soooo exhausted like you said and today it has magically lifted- it definately coincided with AF, I am now on cd3 and it is light. I had just been thinking I wonder if AF is causing it, cos I know my iron levels are ok, and DD is only waking once a night so I am getting a reasonable amount of sleep.
Glad you posted this, I was about to post something similar.