You're tired of saying "yes" to everything but don't know how to say no. You're afraid to tell other's you're upset because they might abandon you. It feels like everyone needs to be happy in order for you to feel okay.
Codependency is the idea that "I'm okay as long as you are okay." Our sense of self-worth, identity and even our sense of purpose can be tied to another person, leaving us on a roller coaster from hell. In an effort to be liked and feel worthy we compromise our values to sustain relationships that don't serve us, leaving us drained and resentful.