Feeling burnt out / tired after starting to learn graphics (OpenGL)

I've been following learnopengl.com for learning OpenGL, and I've completed till Model Loading, and I just don't feel motivated to complete the Advanced OpenGL section.

I don't know if this is just me or graphics programming in general, but I still don't feel like I've clearly understood the whole thing, especially the matrix math. Most of what I'm doing is writing API calls. I've done some abstraction (Renderer, Camera, Model classes), but don't really know where to go next - how do I start building a game, etc.

Any advice / similar experiences?