No way are you a failure! From reading this, I sense that you have been dealing with this for a long time. You have made this far and that's an accomplishment. I don't know how old you are and I really don't care because no matter how old you are you made it this far.
When you say you want to feel 'right' it makes me wonder what your definition of 'right' is. Maybe what you believe as to be 'normal' or to feel 'right' is not possible as a human being. And maybe it is. If it is just wanting it isn't enough you have to go for it. Ask people to help you, see someone, read about it. It's going to be okay.
Being sensitive does not mean your weak, and if you are a little weak that's OK. We are ALL weak in some areas mentally and physically and we can be stronger. Its not easy and it going to be a pain in the neck. You need to accept your strengths and your weaknesses. That is why we have friends and family and other people who help us strengthen our weak spots.
So your sensitive. Me too. It shows that you care and you have a heart. And that is something to be proud of.
You do matter and you do have people you matter to, you just don't know it. Don't give up! Keep going. It doesn't matter what anyone else says. Keep going, get through this so that you will be able to help other people who come across this road and so you can live the life you've always wanted. It's not too late and it NEVER will be.
I hope this helped and I wish you the best of luck.