Is it farther or further?
"to be weighed down or oppresssed by cares or worries, be concerned about," early 12c., a figurative use, via Anglo-French from Old North French carkier "to load, burden," from Late Latin carcare (see charge (v.)). Cf. Old North French carguer "charger," corresponding to Old French chargier. The literal sense in English, "to load, put a burden on," is from c.1300. Related: Carked; carking. Also as a noun in Middle English and after, "charge, responsibility; anxiety, worry; burden on the mind or spirit," (c.1300), from Anglo-French karke, from Old North French form of Old French carche, variant of charge "load, burden, imposition."