] Then we read that she is rejoicing in 'tears of agony' to be at Cleveland,

] Tave also argues that because Marianne has not only allowed but made her emotions go over the top in so many instances (such as getting upset about the way a person reads poetry, for example, or refusing to eat and sleep when Willoughby left Barton, even though she believed he'd only be gone for a short time), that when true misery hits, there is not really anywhere to go with her emotional demonstrations. It's kind of like--what do you do for an encore?
This seems only one facet of Marianne's personality. She appears to enjoy solitary persuits like reading and walking, J.A. mentions her knack for finding the library in each house. In an era where bungee jumping nor scuba diving were unknown or not permitted young ladies and remembering Marianne lacked funds for a horse; With all her pent-up emotion, it's little wonder she indulged in rambles. I suppose she was abit careless to walk through wet grassland but her cold (the encore?) must be real if she's 'heavy and feverish'. Obviously with Willoughby on her brain she's heart sick too; So even Elinor's Tender Loving Care will not effect her improvement. However, she does recover,perhaps as she begins to remember those who love her.
Actually ,I think Jane Austen at this point built up attention around Marianne; From other charecters like Elinor and Mrs Jennings it was all flurry and fuss,care and concern. (A pox on the apothecary for saying 'infection'!) If she hadn't got that cold would Marianne appear so demonstrative,especially as she was beginning to empathize with her sister? Poor girl, I guess she having a difficult,contridictory time of it.