I used to like those things in myself. I was self reliant and I didn't need anyone and I was perfectly ok with that, really. But all of a sudden, living with people who have *lives*, I guess... I just feel so isolated and alone and I've never ever felt like that until now.
I've always been something of a loner by nature. I get along with people really well and I've been told I'm very funny when I let myself be, but I've never been close to anyone. I have a lot of acquaintances but no one that I've hung out with or anything. I just don't know how to get personal. I find it hard to really be a part of something.
I would suggest that, if this is really a burden on you, you begin improving small things every week to maybe make yourself feel a little more "included." Because even though it's fine to be on your own, it still is important to get along with others and fit in -- it's just human nature. After all, in Maslow's Hierarchy of Needs, one need is "Social Needs - Sense of Belonging - Love."
For instance, start by taking part in an extra conversation here and there. You don't need to sit and talk for eternity or share your life story, just give some input - make a comment. It'll become easier and feel more normal to you after time. At first, it'll feel awkward and you might not like it, but you NEED to start with baby steps.
If you're in college, which I'm assuming: Go out of your way to ask someone you don't know in a class a question pertaining to that class. Who knows -- it could lead to some other conversation. If not, at least you'll become more at ease with approaching and conversing with others.
I think one hugely important thing for you could be joining some type of club or group. Search around in your community or college for something you could join. Becoming part of a group with a common interest of yours (politics, reading, science, etc.) is something that could potentially change everything for you. I've had people tell me before that if they hadn't joined a certain group or club they wouldn't have many of the friends they have today, and they'd be an entirely different person.
Good luck and if you need any more help don't hesitate to ask. :)