It's human nature to want to help other people. When you do so, and it is appreicated, it can make us feel useful or wanted. When you do so and it is not appreicated, it can make us feel used. Remember please; that when you do something for anyone, you should do it not for recognition or for any good feelings that may arise. You should do it because you want to. That way, if it is appreicated or not, you can still feel good about yourself.
Sometimes we try to help people, and they can abuse our nature. If you feel this at any point, it is important to assess why you wish to help them. And also, assess with your own intution if they really DO want help, or if they just want someone to rely on and do the hard work for them.