I know how you feel, and I can understand where you are coming from. I do loads of things for people I would normally never do for myself, and like you, I feel its a big mistake, because when I have problems I cannot focus on them myself, I have to think about them.
But there is one thing I try to remember, and that is that I am making the world a better place.
If you ever cannot deal with your own problems PM
me anytime, and I will help and listen to you to the best of my abilities.
And just remember before I leave this post, you are not a mistake. I believe everyone was put on this world for a reason, you could contribute so much to the world, and just not know it. Do not let you get yourself down, you are a good person and you should never change that.