What does "black Care" mean in the following passage from Uncle Silas by J.T. Sheridan Le Fanu?
Waiting for the train, as we stood upon the platform, I looked back again toward the wooded uplands of Bartram; and far behind, the fine range of mountains, azure and soft in the distance, beyond which lay beloved old Knowl, and my lost father and mother, and the scenes of my childhood, never embittered except by the sibyl who sat beside me.
Under happier circumstances I should have been, at my then early age, quite wild with pleasurable excitement on entering London for the first time. But black Care sat by me, with her pale hand in mine: a voice of fear and warning, whose words I could not catch, was always in my ear. We drove through London, amid the glare of lamps, toward the West End, and for a little while the sense of novelty and curiosity overcame my despondency, and I peeped eagerly from the window.