Ask HN: am I making progress or losing track?

(Sorry for the long post)

I am a developer, used to be very well known in my old area of expertise, between my colleagues. I had my own little startup I earned my life of, that was doing well.

At some point I started feeling mediocre, and I decided I wanted to learn more technical stuff. I dropped the startup, entered a fascinating project I never stop learning at, and started focusing in learning more and more about the maths and algorithms of my field.

Since then, I dropped IM as it's distracting, stopped all business like work, and also I'm not caring much about the many new things that are appearing every days. So I could be losing track of one side of technology (new languages, frameworks, methodologies), which I don't care so much about, to focus on algorithms and maths for development in the field I'm working at.

So, am I making progress? I'm learning a lot every day, every time I have more knowledge that I can use (and I use) to do more complex projects. But, I'm not so aware of what the new technologies are, only about the fundamentals.

What's your opinion about this? I feel that fundamentals matter more than the very new technology, but sometimes I feel I could be wrong about this.