if I interpret your code right then you're trying to add a word. if that word exists then just increase the count of that word. Am I right? Then you need just 1 loop (or std::find()). if found add count if not add word to the vector.
What are you doing is: You always add the word if any of the word in the vector doesn't exist more then once. Means if you have 20 unique words you add your word 20 times. the count is also rather arbitrary.