I don't think it is possible to be discouraged after reading this chapter. That clearly is the point of it.
The god of this world blinds the eyes of the unbelieving. What don't they see? The light of the gospel of the glory of Christ (2 Cor. 4:4). How many professed Christians don't see that it is about the glory of God in the face of Christ (2 Cor. 4:6)? The gospel is about God's glory first and our salvation somewhere down the list.
The purpose of affliction and brokenness is so that the life of Jesus might be manifest in my circumstances (2 Cor. 4:11). To say it another way, I die with Christ so his resurrection life can be mine. No dying, no resurrection. Death brings life (2 Cor. 4:12). You don't get a resurrection life without a death.
The contrast between the treasure and the treasure container is so hope-giving. It's not about me, it's about the treasure.
2 Cor. 4:16-18 are the most sublime in all the Bible. Nothing pulls me through tough times better than these verses. The eternal vision of glory dwarfs the affliction of the present!