The Vitamin D thing is actually legit. Depending on where you live, you may not be getting enough sunlight (not all sunlight produces Vitamin D, has to be the right time of day/position of the sun, and the correct season) which naturally produces Vitamin D in your body. I live in Massachusetts, you can only produce significant amounts of Vitamin D up here during late Spring to early Fall and only during a few hours in the middle of the day so up my way a lot of people are Vitamin D deficient. Now I'm not saying a low Vitamin D level is the cause of your depression but if your levels are low it can and likely is making your depression and anxiety worse. You should get your levels checked to be sure. Again, raising up your Vitamin D levels probably won't make your depression go away but if you are low, it could be the difference between wanting to swallow a bottle of pills and just feeling a bit down.

Also I think part of why you (and myself, and I'm sure many others) feel more sincerity and love from our fellow redditors is because we only know each other through our shared pain, and people who feel the kind of pain we do tend to be much more compassionate toward others who are also in pain. "Normal people" don't understand us because their natural instinct is to keep themselves alive at all costs and to move forward and not look back. To them the idea of wanting to die is so foreign they can't begin to comprehend it. That's why it took me so long to find a good therapist, there are really only two kinds out there. The kind that are normal people with normal emotions and thought processes who want to be therapists because helping people makes them feel good about themselves, and I'm not saying anything is wrong with that, they certainly mean well, but then you have the real therapists, those are the kind that are like us, they've shared in our pain, they know how we hurt because its how they've hurt, they want to help us because they've seen the darkness and they can't stand the thought of anyone having to live in it. They save us in part to save themselves too.