Dear Yis, I have tears in my eyes. I am feeling so sad for you. I know you may not like this, but you pointed out the fact that you have self esteem issues, that you are insecure. I really want you to think about that when you are assuming that others don't like you or that they think you are nothing.
Your self esteem issues are the main issue from my point of view. Not believing in yourself, not believing that you are wonderful, that you are special and smart and good looking, etc can make you feel like nothing.
Yis, you need to start realizing how wonderful, how important, how special you are. AND...Believe it! Because if you don't, no one in your life will!!!
Basically that is the way we all work. We meet someone who thinks they are worthless and we believe it! That person could be someone I want to know, but of their attitude tells me they are bad, or mean, stupid etc. why would I want to hang with them. So Yis, please start holding your head high. Anyone who thinks less of you is not worth your time!!!! Good luck to you