@David *********
>I’ll have to confirm whether or not it was simply an extension.
You can confirm by looking in your passport (that you kept, and didn't let the agent keep, correct?). An extension of stay looks like this below:
(the key word in the stamp is "Extension of stay")
>If I were to quit a job with plans to return to my home country, do I have to switch to a Tourist VISA right away?
As
@Robert ******
said, you will have to cancel your work permit and extension of stay, and then get either:
1. A new extension of stay that you qualify for. MOST people can get a 60 day extension of stay based on unable to travel due to COVID-19. The last day they are selling this extension of stay is September 27th.
2. Get a 7 day extension of stay denied stamp (IF you don't have any other valid reason to stay in Thailand, like retirement, family, etc). At the end of the 7 days, you *MUST* leave Thailand.