I Battle Depression

Sometimes I just want to eliminate myself from this world. I give chances to new people, conditioning myself to think they're different from others. They all have something in common - they all eventually lose interest as soon as I open up myself and give them my all. They made me feel special like stars in the dead of night, when in reality, they just lie and will say whatever they want to fulfill their selfish needs. Why is it that I keep giving chances to people and never learn my lessons? Why do I trust so easily and allow myself to even think that they won't hurt me? It's my fault for giving people a chance, and it's even more of my fault that I never learned my lessons. I will never understand why people like to play with other's emotions. Do they get some sense of satisfaction over it, like they've gained a medal and move on to the next conquest?