Oh yea, that happens to me every once in awhile.. I hate it! Sometimes I just want to sit and cry for no reason at all, you feel lifeless, tired and no ambition to do anything... I do think it has alot to do with menopause, I've been going through this for at least 8 years, and I am sick and tired of it, wish it would just go away!!
Hope your blues go away soon, mine so far have always gone away almost as fast as they've come... all of a sudden one day I wake up in the morning and I feel great so much energy and no more feeling blue, until the next time it hits me again.