Heh. I've had the same thoughts. Around 6 weeks, I was asking myself and my sponsor, "why am I feeling this good and everyone around me seems to be struggling? Am I just deceiving myself? Setting myself up for the other shoe to drop?"
My sponsor's response: If you're feeling good, enjoy it. But know that eventually, whether you like it or not, you're going to have to confront a difficult issue. The question is, are you doing all you can to be ready for it?
Now that doesn't mean living life in fear of relapse or waiting for something bad to happen. He explained it meant that as long as I'm doing everything I need to be doing to protect my sobriety, that I'll be okay.
I'm almost 6 months in and I still feel on top of the world. But in that time, I've also lost a romantic relationship and my dog had to be put down 3 weeks ago. But I'm still so grateful for how much better life is now than it was when I was using.
So enjoy it! You deserve to feel good!