Nah, the feeling's not one I'm unfamiliar with. I'm 28, myself, and while I'm working my way towards getting my Master's Degree little by little, there is the sense of 'what do I have to show for it?'. I work on my writing, little by little, especially since this spring semester renewed my sense of purpose in that front, but even now there's that inescapable feeling of questioning oneself. Really, I can't tell you how to beat a feeling like that, other than to just focus yourself on what you're doing now, and taking life one step at a time. If you worry too much about the future, you end up losing sight of the now, and instead just make yourself feel worse and worse in a self-defeating manner. There's nothing to be gained from that other than more woes and worries about your future, and an even more diminished sense of self-worth. 'Try to stay positive' is a cliché, perhaps, but it's one that holds some merit and truth to it. Don't let fretting over an unwritten and uncertain future keep you from trying to be happy in the now; especially when you being happy is the key to future success in the first place. That's about all I can offer ya.