I was like you when I was 18. Life does have its moments. In my case 2 of them. I'm 30 now. I completely understand your fear of rejection. I overcame it. So can you. It's a spiritual thing, usually takes several years. Rejection doesn't even hurt much. I have been rejected thousands of times, and once you understand why people reject you (and most others), you don't take it personally anymore. I'm not afraid much anymore.
All that said, life is not worth living if you are like me. Killing youself also isn't worth it, but I'm ready to leave at any time.