>>1 The reason of your isolation is your basic shyness and lack of social skills. Your case is extremely common, and it boils down to this: if you are withdrawn, people will start ignoring you, because getting some interaction from you requires too much energy. This energy will be better spent on other people which respond more with less effort. You then enter into a vicious circle, because your lack of social exposure prevents you from gaining basic social skills, which makes it even more difficult to get into contact with people.

Fortunately, there is a very simple way of breaking out of that vicious circle. It's simple, but not so easy, as it requires conscious effort from you. If you are not ready to sweat on it, you can just forget it. You basically need to review your interests, and enter into a group activity based on it. People socialize naturally with other people with whom they share common interests. So in this way you will compensate for your initial handicap. But that's just a starting point. You still need to reach out for people, and really put an effort in developing your social skills (hint: try to have more empathy for them), otherwise you'll waste your initial advantage.

Good luck!