I've had all sorts of gaps in my career. 6 months, 1 year and more, to explore different domains. I'm in computer graphics/front end, pretty fast paced.
Nobody ever asked.
Please, never feel guilty about taking a single month off. If your body needs rest, you need to listen to it.
I think the proper answer is "I just took some time off between jobs." Sounds fine, sounds like you took advantage of an opportunity, and doesn't sound like you're somebody that had a hard time finding a job.
Not every industry is like this, but tech has little reason to care. If anything, employees with more life experience are a benefit to the employer.