Google is your friend
@Jef****
, It shows theres a labor dept in Nathon in between the Police Station and the Tesco. That'd be where I'd start. You need to verify IF you can hold a work permit on the extension you have. IF you can, find a job, get a work permit and start working.
IF you can't, find a job, get the documentation, go out of the country, get a 90 day Non-B visa from a thai consulate nearby, come back get your work permit and work.
It's far from stressful. It's just the way things work here