When I had depression, I had similar symptoms like you. I had same deep pit in the morning and unable to sleep at night.

I tried exercise, read Feeling Good book, took different vitamins etc. None of this really helped.

What finally worked was giving into my depression. I would come back from work, listen to sad songs, cry like a child, pray, and drink until I passed out. Within a few days, I would wake up without pit in my stomach. Hangover was another story. Within a couple of weeks, I was not depressed. Depression turned into anxiety. And anxiety was a lot easier to deal with than depression.

Once depression was mostly gone, then I was able to use CBT methods to deal with my anxiety.

It is really hard for people who never experienced depression to understand what it feels like. It is worse than hell. I am sorry you are going through it. Just take one day at a time.