I was reading a book written in the UK and a character stated that speaking to her sister made her "feel Humpty". I am not sure what she was feeling, as the rest of the dialogue gave no clue. Can anyone help clarify this?
From Wikipedia: https://en.wikipedia.org/wiki/Humpty_Dumpty at Origins
"...According to the Oxford English Dictionary, the term "humpty dumpty" referred to a drink of brandy boiled with ale in the seventeenth century. The riddle probably exploited, for misdirection, the fact that "humpty dumpty" was also eighteenth-century reduplicative slang for a short and clumsy person. The riddle may depend upon the assumption that a clumsy person falling off a wall might not be irreparably damaged, whereas an egg would be. ..." [my emphasis]
Your meaning could be either short or clumsy depending how well each fits the context of the dialogue.
Taking the idea of reduplicative slang a little further, and as is noted above in the comments, possibly empty.