Feeling used

I am a very giving person and I feel like the people around me are all taking advantage of me. I am noticing it more as I feel once they have what they need out of me weather its a lift somewhere or money or advice they tend to ignore or treat me like shit. I am feeling like when I need people or I feel alone, i have no one there. I live a very happy life, i am outgoing and easy to get along with, i am engaged to a wonderful man and i have the priveledge of not having to work. Emotionally i feel like i am starting to lose it.