This is a question for your manager. If you caught something contagious, you'd be protecting the company by taking a few days off and not spreading it; but it sounds like your issue is stress related.
Pro tip: When you look at other examples, take a few moments to compile notes on what you find. You'll start building a knowledge base which will become amazingly handy in the future, for you and other potential future hires. It'll also work wonders for your image, especially when the documentation culture tends to anarchy.
It's always a good idea to ask your manager how things are going and if you're meeting expectations, especially when you're new. Your success is your manager's success, and his job is help you do that. Asking how taking a day off or two will be perceived is perfectly pertinent.
Can taking sick leave be a reason for my termination
Sometimes an employee may have to stop working because of long-term ill health. They may resign, or you may have to consider dismissing them
If the employee can’t do their job because there are no reasonable adjustments that can be made, it may be fair for you to dismiss them, even if they’re disabled
This is clearly written for cases where the employee cannot perform their duties due to long-term illness, and no reasonable accommodation can be made for them (ie. not your case).
tl;dr Ask your manager