Man, the mood swing part rings true for me. In my case they're usually 1-2 weeks. There's some anxiety/depression on my mother's side of the family but I wouldn't say that I've got any issues with it.
Now I'm curious as to whether the mood swings are more common, or whether that's actually something I should look into. If there is an underlying issue I need to resolve then it might have been masked by my relatively good run of things.
It can worsen (or improve) with age or biology. If you can, it could be worth finding a doctor you trust and talking to them about it, and try to determine whether it needs to be addressed or not.
Now I'm curious as to whether the mood swings are more common, or whether that's actually something I should look into. If there is an underlying issue I need to resolve then it might have been masked by my relatively good run of things.