4-month résumé gap, advice? (St. Louis)

My résumé shows a gap from a layoff and some health issues. This is my first time dealing with any of this. I am nervous about being filtered out.

I listed the volunteering and course under the same dates and kept the explanation to a sentence in the cover letter.

I was hired after a 4-month gap. The manager said the skills test mattered more than the dates.