Just want to echo Patrick's answer. He's pretty much got the right idea. Most rankings not on page #1 will jump all around. I would only be really concerned if it dropped from page #1, down to page 4-5 etc. Also, I would also agree that you don't need to focus too much on rankings week to week - and in addition - I wouldn't focus on rankings for a single keyword too much.
To see if you have some sort of site-wide issue, I would check your Impressions in Google Console Search Analytics. See if your Impressions have dropped in the same timeframe.
I would also look to queries where you already rank page #1 - and be sure those are optimized for CTR with titles and descriptions, and then see if you can find out if users are happy with those pages - maybe with goal tracking or some sort of measurement to see if they are converting etc.
Then - really focus on "local SEO", here's some resources:

I'm worried about doing redirects because that is a lot of redirects!