Why do I feel like nobody cares about me?

Why do I feel like nobody cares about me, even when I have family and friends that very clearly do? Its this nagging feeling of drowning and helplessness and my mind starts going like an engine that won't stop. I sometimes cry myself to sleep just because my mind just keeps going and going, telling myself that nobody cares about me and that I should just end it all. I don't want to feel this way anymore and think this way anymore.