<human>: Can you condense the text into a few key points?

I do not where to begin, or if this is the right subreddit, but I feel I need to just ventilate my thoughts. 

I have a lot of friends, of both sexes. I have close friends. My family  loves me and I love them. My friends respects and accepts me for who I am. I have no problem with talking with strangers and making new friends. Girls thinks I'm funny, intelligent and a wonderful person. Guys thinks I'm smart, funny and well fitted. I'm getting invited to parties, love my social network and love my ongoing education. I love almost everything about my life, of course there are things I'd like to change, but at the moment, these can't be fixed due to some things..

Anyway. Despite my family's love, my friends acceptance and my situation, I still feel lonely. I just don't really know how to describe the feeling, but it feels like I've built up a fake world around me to live in, to make my life worth living and that I've recently started to break this illusion down. I know this isn't a fantasy world I live in, and I know I have real, close friends, but still, I can't really accept it. I do not feel good, even when I'm with those who are the most important persons in my life, my mum, dad and brother. When I'm in their vicinity, I always get reminded of that one day I won't be able sit down with them, chatting or just be close to them. This feeling is killing me and I really do not know what to do with it. The feeling came last year when I moved to another country to study. I thought it just was homesickness, but since it remained even during the time I went home over Christmas and summer, and is still present now, a year later, I think it maybe is something else.
<bot>: Every time I see/meet/talk to a person who is important to me, I get reminded of that I one day in the future won't be able to see them any more.