where did I go wrong?

A couple of people just recently told me that I am a wonderful person. I'm far from perfect, but I believe I do have a kind heart. I may be indifferent to people I don't give a damn about but I give my heart to those I care about. I would love them, care for them, go out of the way for them. As long as they are happy. So much so that sometimes I wonder if I am taken advantage of. Maybe they don't really care about me as much as I care about them. If that's really the case, how stupid I would be. If I were really such a nice person, why do I feel that I am not loved? Why do I feel that the only people who truly love me for who I am are my family and those people I left behind? Why do I feel so lonely? I have so much to give yet I can't. I have so much to share yet no one to share with. It's so sad isn't it? Where did I go wrong? Maybe I'm confining myself in a closed space where I have nowhere to run. For no matter where I turn, I meet a dead end. I may sound ultra melodramatic but sometimes that's how I feel. My life sucked out of me little by little. Sadness turned into anger, anger into bitterness. But where did I go wrong? I need some answers.