You're right, Charlotte Bronte had no medical training. Nor did Currer Bell. She did, however, provide a good description of how it feels to think that you are ill (and be depressed I suppose), given by her male character in The Professor. One paragraph ends with the sentence, "I was temporarily a prey to Hypochondria." Here's the next paragraph"
"She had been my acquaintance, nay, my guest once before in boyhood. I had entertained her at bed and board for a year; for that space of time I had her to myself in secret; she lay with me, she ate with me, she walked out with me, showing me nooks in woods, hollows in hills, where we could sit together, and where she could drop her drear veil over me, and so hide sky and sun, grass and green tree; taking me entirely to her death-cold bosom, and holding me with arms of bone. What tales she would tell me at such hours! What songs she would recite in my ears! How she would discourse to me of her own country - the Grave - and again and again promise to conduct me there ere long; and drawing me to the very brink of a black, sullen river, show me, on the other side, shores unequal with mound, monument and tablet, standing up in a glimmer more hoary than moonlight. "Necropolis!" she would whisper, pointing to the pale piles, and add, "It contains a mansion prepared for you."
It goes on for a couple of more paragraphs. It is all near the end of Chapter XXIII. You can't make up stuff like this, but she could.