Do you say yes to everything because you don't know how to say no? Do you say yes even when you don't have the time or resources to actually commit to what you are saying yes to? Do you say yes because you don't want to hurt anyone's feelings or risk upsetting them?
Maybe you're not a "yes" person. But do you say no to everything? Do you know you can't commit your time and resources to all that is asked of you, but instead of choosing you instead say no because you feel like this is the only way to be fair?