Awwww, I really do feel for you, you have got yourself in to a vicious circle and I think you are aware that only YOU can break it.
Its easy for us to say "just go do something, anything, the first time will be hard but it will get easier" some of us have been where you are now. But that is us and you are you. What you are feeling is genuine and valid.
Reconditioning your thought process takes determination, it takes willpower to make yourself see things differently. We can suggest things for you to do and try but only YOU can choose to make the steps necessary to change your life - and it will be a change for the better, you know that.
Your s seems genuinely concerned for you - why not enlist his help with this. Ask him to go to/do one of the 7 things you thought about, make it less scary by doing it with someone you know and trust. That way it takes the fear factor level down a notch or two. You will hopefully see that there was nothing to fear, that is was ok and you can do it again on your own.
Tad, I feared going on out my own, doing new things, meeting new people - I felt sick with nerves, even drove to a few places, sat in the car park and then drove home cross with myself that I just missed out on something I really wanted to do through fear. So I broke it down - go for 15 minutes, if I don't feel comfortable then I can leave, but I have to stay at least 15 minutes - I am much more confident going to things now or trying something new (in the beginning the fear of looking at idiot held me back, what would other people think) I still have the 15 minute rule, but now I have new friends so I don't go to or do many things alone now - but I know I will be just fine and most likely enjoy myself if I do.
You come across as a really nice guy Tad, don't let the world miss out on having you in it and you miss out on the world.