Your choice of words is telling. Justify to whom? It's your life; do you want to get better or faint/fall down the stairs again and not have a choice?

I don't know if you are afraid you will have problems with not doing "something" or that you will learn you are not indispensable and the world will keep going around well without you. Panicking from either of those alternatives is not healthy. It sounds like you are giving away too much energy trying to keep from panicking; think what more you could do if you weren't afraid but doing it for the joy of it?