Depression if often an inward turned and suppressed anger. When I found my anger I felt that if I let it explode it would incinerate not just me but this entire world. I had no idea what I was angry at or about. I certainly could get mightily pissed at anyone and anything, usually out of proportion to their "offense". It feels like a boundless fury. It's terrifying.
I have an advice if you would care for one. Do not allow yourself to act it out on live targets or inanimate objects, it will not help, and will probably leave you feel ashamed of yourself or in trouble with the law. If you like you can use some of that fury to fuel your exercise, or dance (dance it out like the gals in Grey's Anatomy)
But also, do not bury the anger. If you have a therapist ask her or him to help you. If not, read, a lot of people write about it, articles and books.
I am currently reading a book by Arno Gruen "The Insanity of Normality. Realism as sickness: toward understanding human destructiveness". A slow and hard read even though it's meant to be read by lay people.
But it helped me do some soul-excavations. I remembered a statement I heard too many times as a child: "if you keep going like you are, no one will ever love you". Most of us as children were issued a very similar awful blackmailing ultimatum: "You can't be yourself! You, as you are are horrible and unlovable. For your own good we are gonna change you." We need to be loved, so we aquiesce. Gruen calls is betrayal of self. It's a frightful thing.
I saw how this lay in the center of my self-sabotage and low self-esteem, my depression, and my overeating, my inbility to truly love myself or anyone. See I was concurrently trying real hard to be nice, so someone will, please!, love me!, and acting out "f-u, I don't f-ing need you!"
It wasn't my parents' fault. They were likewise broken in their childhood. And I wasn't my fault. I was a helpless little being.
It Just Was. (And it isn't anymore) So now, here I am and given a choice between love and hate, I choose to love myself. (though remembering that choice from moment to moment is another day's story

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I hope you find this sharing relevant to your discovery. Take heart that in cracking that shell and seeing that anger you are getting an upper hand on your depression.
Peace to you