When is Enough Too Much?

Do I give too much of myself?
I am what you would call a giving person. I express affection through giving and doing things for people. I like to do things for people, to show them that I care. In the words of a wise woman, "It's one of your love languages." But this can get me into trouble in a few ways.
First, it can lead to people taking advantage of me. People assume that because I am a nice person who will always do nice things that they can ask me to do anything and I will say yes. Sadly, this is often true. Even worse, while I am doing the "nice" thing that I don't want to do, I resent the person who asked me for the favor. I get upset and frustrated and stressed out and don't like the person that I become. I guess I just don't like to be asked to do nice things. I like to be able to see needs and fulfill them without being asked.
Second, I take care of people too much. I sometimes forget that people need to take care of themselves. And I never let anyone have a chance to take care of me. I need to learn to do that.

This last part is a common problem with women I think. We are raised to be nurturers. We are taught to take care of everyone and put the needs of others above our own, to sacrifice for our children and the men in our lives. Then we whine and complain about how we don't know what we are doing to drive men away. Well, we're taking too much care of them. That's what drives them away. Women, no let me rephrase that, I need to remember that they're big boys and they don't want me to pay for things, to do everything for them all the time.
The first step is admitting you have a problem, right?