I think
depression can be a combination of things - both physical and emotional. I used to get mind blowing headaches, which was partly caused by my depression, and then because I had them, it made me feel emotionally worse. It's a nasty cycle. From what you've described, you've been under a ton of stress, getting married is up there in the stress meter! I know when I've been ill, which I went through recently, it sure made my mood drop.