I "woke up" and now I'm nervous?

I recently turned 20, and I've noticed that I'm all too aware of things now, to the point that it's emotionally painful. We were sitting at dinner and some people were saying "Better finish that food; people are starving in Ethiopia," and everyone laughed and joked about it. It made me really uncomfortable. I thought about the faces and emaciated bodies I've seen on TV, and it just wasn't funny. We walked around downtown and into a beautiful, elaborate hotel. I was made painfully aware that people are living in huts with dirt floors, praying for clean water. It made me sick. I can't laugh anymore. I can't have fun anymore. Everything I do makes me feel guilty. I imagine people who have no friends or family members to help them, people with terminal illnesses, people freezing on the streets, and all kinds of things that make me feel guilt for existing in the state that I do. I feel sensitive to this stuff now. I'm scared of what might be after this life. I can't focus on anything in the world, because it feels meaningless in the face of an eternal abyss that seems to be awaiting me. I'm terrified. What should I do, and what does this sound like to you?