I think you answered your own question to start with -- there is something about having the responsibilities of taking care of yourself that is causing a great deal of anxiety. I think the next question to ask yourself is, "What is the risk of growing up and taking on all this responsibility?" This is a common anxiety for people by the way -- some worry that without the protection of their parents they will fall flat on their face and be a failure, others worry that when they take on the role for themselves that their parents had, this will be the end of their relationship with their parents, and other people have other concerns (of note, it doesn't have to be one or the other, it may be a combination of different concerns).