Also late but I definitely recommend journaling. The most stable points of my life are those where I've consistently kept a journal.

I usually have at least 2 going at a time - one I carry with me, one is at home. Occasionally I'll have a separate sketchbook or mood/exercise/whatever tracker. So, if anyone wants to read them when I'm gone, the chronology is all weird.

I've found that, more than getting the feelings out (it usually doesn't feel cathartic to me, not really) I'm better able to turn around my negative thinking. It's easier to look at these thought patterns and evaluate them objectively if you're slowing down to write it all out. So, often (not always) if I'm getting some breakthrough depressive symptoms I can sort of talk myself out of it. Or at least, recognize that those negative thoughts may not accurately reflect reality, even if I'm still kind of stuck. When I've already gone down the rabbit hole and can't get out, at least the journal helps identify the areas where I need to improve. I do sometimes reread, and see patterns.

I started a project lately (I like projects) where I'm taking a photo of myself after I finish journaling. I think it'll be interesting to have a visual record in addition to the written record.