Good at everything, great at nothing

I have a lot of interests. I think that I'm mediocre at most of them. In fact, it's kind of a relief when I am markedly bad at something. This sounds cocky and pretentious, but if I'm good at something, I feel that I should pursue it. Like writing. Like singing. Those are the two things in which I feel like I should pursue something.

When I was a kid, I was highly praised for my singing abilities. Singing was a part of my personality in a way that my name was almost synonymous with singing. I got older. From lack of encouragement and listening to loads of people telling me to pursue something "stable," I kind of left music behind. 

Then there's writing. I've a sneaking suspicion that I'm not the great writer that I think I am. I majored in English, and maintained good grades, but I don't know that my writing ever had that true gleam of greatness that my contemporaries possessed. Still, I stuck with it, and I now write (albeit pretty unglamourous stuff) for a living these days, and have for the past 4 years. 

I'm not meaning to whine, just feeling this ennui about turning 35 and having nothing to show for it, career-wise. I _do_ have an okay job, and make a good living, and back when I lived on the more prosperous side of the country, I had a great job. 

I guess this was brought on by hearing of the success of a friend, and having that "I could have done that too" feeling. If only, if only, if only... I'm also fighting through some major writer's block.