Wait a darn minute; what happened with the engineering-related jobs you were going to apply for!

Anything is better than retail for you it sounds like

Send your resume to civil engineers and land surveyors like I told you and ask to be a "rod man" for the summer.

Check out summer jobs at colleges and municipalities near your home, or see if you can get a summer tutoring job teaching grammar school kids maths and/or reading so they can keep it in their heads for next Fall.

No settling for something you totally don't want and which is stressful! If worse comes to worse; get a job in a hardware store, that's closer to engineering than groceries!