"when thou hast shut thy door, pray to thy Father which is in secret"
It is possible to be at peace in any situation. Inside, there is a space to be discovered, which is larger than any outer space. Conceive of and fit it out as you wish, or, better, let the Higher Power reveal it.
The cure—the cure—to all anxiety and depression is the discovery of and the residing in this space.
How does one achieve that? By practice, for hours, for years.
The world cannot offer peace. But the inner space can, and it is the only thing that can offer it.
Spend enough time there, in the acknowledged and recognised presence of God, and two things are discovered:
All that does not matter is controlled automatically by God.
All that does is guided automatically through me by God.