What is the word for shocked and overwhelmed?
Several near-synonyms are available, each with its own connotation and degree of formality: flabbergasted, floored, knocked over, bamboozled, etc. The closest might be "stunned" because it implied the "shocked" aspect. But the underlying meaning -- to be physically overpowered by an abstract or mental assault, causing temporary paralysis or inability to act -- is best captured in the phrase "knocked off my feet." This phrase reflects the "floored" aspect of the question. Remember Donald Hall's admonition: "The definition of a word is another word." In the terms of the linguists, the signifier and the signified will always have some distance between them.