This is a tough problem to overcome. That's because learning social skills takes time and practice. You lost a lot of time spent doing solo things like the games on the computer. So you have a lot of catching up to do. As with anything new, we tend to make mistakes in the beginning. No one is very good at something that they are new at. So you will have to endure some pain to come out of your shell. Make up your mind that the pain won't kill you. It won't, if you see it for what it is - struggling to succeed at something you don't know much about. The more you try, the more you will learn.

You already show a warm interest in people, so your situation is far from hopeless. You may find you do best in situations where there is some activity to structure your interaction with people. For that reason, I recommend volunteer activity. Your help will be much appreciated by someone somewhere. It may involve you doing something that feels kind of boring for awhile. Your willingness to put up with that is the gift you can give. It will take time, and for awhile it may seem that getting involved is not getting you anywhere. You have to be willing to be very patient.

I'm glad you are developing a relationship with your therapist. There is one thing about that which I would warn you about. Being with a therapist can feel very safe. The T is always focused on you and interested in whatever you have to say. That is not how interaction with people happens outside of the offices of Ts. So it can get you to where you only want to interact with your T, where that happens more easily. Force yourself to do things that feel kind of risky. That is how you will learn to cope.

In the end, trying to come out of your solitude will be worth it. Being alone is not fun for anyone. There are no computer games that can give us what we need as humans, which is contact with other humans. Good luck. You can do it.