I understand very much the feeling about having a hard time getting out of your shell while having the fear that once you get out of your shell, other's won't like what they see.

I cannot tell you you are definitely wrong, as I do not know you.

But maybe the way to learn how to get out of your shell, and being likable doing it, is by learning from your failed attempts.

Also remember that people are selfish. They do things that make them feel good. The person that involved you into the circle of friends, he does so because that makes him feel good. It is not impossible that they think you barely improve their friendship and that they offered you a pity friendship. But even if that were the truth, you still make them feel good about the pity friendship they offer you and there is no reason it cannot change into a true friendship.

If you feel so grateful to this person, why not tell him? No need to offer money, except out of politeness. Make sure he knows that he is being very succesful at what he is trying to do.

I am sure there is room for improvement in your life. In whose life this is not true? But are you sure you are not underestimating yourself? If you were bad company, they wouldn't keep you around. Yes, it is possible that someone is invited because of pity. But no one suffers through bad company out of pity.

If you really had ideas about suicide, sounds like you had the way you wrote it, consider talking to a professional about it. It won't harm. Your life improved a lot the last few years, but you are not satisfied. No reason it cannot keep improving the way it did.