Discussion Groups / British English / September 2004

There are other meanings of care.

See http://dictionary.reference.com/search?q=care

<quote>
  1. A burdened state of mind, as that arising from heavy responsibilities;
worry.
  2. Mental suffering; grief.
  3. An object or source of worry, attention, or solicitude: the many cares
of a working parent.
  4. Caution in avoiding harm or danger: handled the crystal bowl with
care.
  5.
        1. Close attention; painstaking application: painting the window
frames and sashes with care.
        2. Upkeep; maintenance: a product for the care of fine floors; hair
care products.
  6. Watchful oversight; charge or supervision: left the child in the care
of a neighbor.
  7. Attentive assistance or treatment to those in need: a hospital that
provides emergency care.
</quote>

In your sentence: "In prison I'm worn out with care", 'care' might mean
'mental suffering', perhaps grief, anxiety, remorse, a sense of injustice,
or some other form of mental distress.