I haven't worked on my compiler for about the same time for a number of reasons, one of them being that I wanted to implement one missing feature, but hadn't yet figured out how to do it and it looked like a big thing. I have now mostly figured it out (and settled on a less ambitious/efficient implementation just to make the progress easier), so, I'll implement it eventually, step by step, just like I did other things.
But this all is nothing compared to things like going out of physical shape. About 15 years ago there was a period when I didn't play my guitar for 10 months straight. It took me some 3-4 months to regain what had been lost by not playing (there was no injury involved). I've played ever since and I've made some big improvements in the past couple of years.
We sometimes embark on big adventures and take on complex projects and we get stuck and frustrated with some obstacles or just plain burn out. It happens. Sometimes we hit something (in the project or in life) that causes us to reassess our abilities and rethink our priorities. It's fine too. So long as you understand what's happening. I have, for example, haven't worked on my OS code for about 10 years now. The last big thing I did was a full FAT12/16/32 driver with a test suite. I realized that the OS project is a bit too big for me time-wise. My Smaller C compiler turned out to be a more contained and manageable project. In just about two years of work on it I have completed most of what I wanted, sometimes even more than anticipated. It's usable on 2 architectures (self-hosting on one) and 4 OSes. Kinda neat. I didn't make a usable OS in 7+ years in contrast, even though many parts are done or are more or less straightforward.
Anyhow, we do it for fun. And as long as it's fun. You may resurrect your interest a few days or weeks or months. Or not. Which is fine too.