Hi, sorry to hear of your suffering.
If you have been diagnosed with clinical depression, it will probably show up on your health records, and be what insurance companies consider a pre-existing condition for which they might not cover you. You might be waiting to get onto his insurance for "no" reason? Why not go ahead and make that appointment?
While I won't diminish your feelings of sadness, there are many here who suffer with depression far about the "over the top" scoring. I say this to encourage you, because you can live with high scoring. (((hugs))) But I still feel for you being so sad.
I understand your statement about nothing "causing" this episode, in the strictess sense. However, since you felt it coming on a few days ago that does suggest some changes that occurred to spur it on? Such event(s) could be food allergies (you ate or are eating something you don't usually or you're eating more of it lately) to hormones (these chemicals can wreak havoc on us through our brains) to improper thinking/responses to situations in our lives (see 10 cognitive distortions thread sticky posted at the top of psychotherapy forum, and work on them.)
Don't put off getting help, please. Now's a good time to begin healing, and feeling better. It can happen; hang in there.