Oh wow, let me see, where do I even start.
Depression is not a “dark phase” and it's not something you go through when something bad happens. That's something else. I don't have the medical background to say for sure but I believe the term is “bereavement”.
Depression is a medical condition with no known cure, which strikes (“episodes”) periodically, and usually for no apparent reason. Bipolar depression is a completely different condition, but since a lot of symptoms are shared, support and therapy (but not medication) can be the same.
“Before you go talk to a doctor…” <- let me stop you right there: NOPE. This kind of “advice” is unhelpful and extremely dangerous; in the case of depression it can cost lives. If you suspect there's any slight chance you might have depression, go find a doctor.
Finally, commercial links on a post about mutual support are IMO extremely bad form.
So please, we don't need “contributions” of that sort.