It's probably not ever entirely an either/or situation but some combination thereof. I think it makes sense to consider what it is, for instance I went through grief that due to a couple of bereavements that occurred a little too close for comfort, which then turned into a major depressive episode. At first I looked at it as being situational, and didn't realize when it became more than that.. but when I went for help and it was looked at as being purely pathological, that wasn't very helpful either. Better to be holistic, I think, in looking at it as the complex experience it very likely is.

I saw this chart in a book I was reading recently, and I don't know how scientific it is, but maybe it could be helpful in considering what's at play:



Maybe write down some of your specific feelings about it, and which you think those specifics are each attributable to? Might be a good way to map it, and to differentiate as you say.