I’m a recovered Catholic, have extensive experience with depression, and believe enough in an underlying “truth” to respond to your question. This isn’t an attempt to dictate whether you are depressed and to what extent such depression requires a medical cure.
If you are Christian, then you likely believe in God, Jesus, a Holy Spirit (at least that’s true for Catholicism), that you have a soul, and the Devil.
I would begin by suggesting that you are letting the Devil’s influence hold sway. The Devil’s currency, in addition to capital E Evil, includes fear, self loathing, pessimism, etc. The Devil also deals in trickery, and the nature of dark energy is that it pretends to be alive and holds people captive.
Inside, you are likely clinging to this energy, because you have been seduced into the belief in its reality. The religion of your personal suffering is inhabiting and informing your heart soul and likely has such a grip on you (and you on it) that there is only the fleeting possibility of achieving what you are aspiring to achieve. You are holding on to a boulder, and you are aspiring to swim without letting it go.
So the first thing is waking up to that possibility and resolving to dispel that influence.
The second thing is inviting God’s love, inviting the Holy Spirit, inviting Jesus’ light to live within your heart and soul. I think a pervasive mistake with Christian religions is the persistence in this idea that God is “out there” and we are perpetually appealing to some external entity with selective hearing. God isn’t the tooth fairy or a genie in a lamp. God is like sunlight in that He bathes us all in life-giving light. Witness your own despairing. Why haven’t you dropped dead from grief? Why haven’t you offed yourself to end your suffering? Is it possible that God’s love is keeping you afloat in spite of your best effort to hang on to that boulder?
The key words going forward are ones such as open, cultivate, welcome & invite. Rather than let the Devil foul your soul, invite God’s love and light to live inside you. Make a practice of growing that light within you, and when you can, take delight in it and share it with others. Recognize the peace that it brings and when you can share that peace with others. I’m not saying evangelize. I’m saying share the light and the peace.
This is what it means to be saved. It means letting God’s light inhabit you and experiencing the immediacy of God’s touch within you.
Some Christians, unfortunately, treat Original Sin as an end in itself. There is too strong a chant of “We are sinners!” Sin is turning away from God, shutting out his light, and being tricked by the Devil that we have cause to despair. You’ve been tricked. Perhaps we all have. But now that you have an awareness of what’s real and what’s illusion, you can address the trickery with forgiveness and let go of the need to resolve your problems. They are also illusions. Just let them go and step into the light. Let yourself be saved and live with God’s love inside you.