Does the company have any policy that dictates a doctor's note after a specific number of days?
If so, take the max you can (usually 2 or 3) without the note. If there is no policy, take the same 2 or 3, guilt-free. You don't have to lie. Just say you won't be able to make it in.
And when you come back and they ask how you're feeling, "much better, thanks" is all you need.
And no guilt. Don't forget the reason you took a job that pays. Cimarron's got it right. Your loved ones are #1.