Something's up.
Stress is usually the trigger, as it's something I'm still not that great at dealing with. With the baby related activities, costs, and general uncertainty of how to raise a human piling up, and work projects somehow needing to all be finished prior to the baby arriving, there is plenty of stress in my life right now.
Luckily for me, there's enough of a pattern with this stuff that I'm not totally unprepared when depression rears its head.