Have you considered setting up an infopass appointment and trying your luck at getting a work permit extension that way?

https://infopass.uscis.gov/

As for switching careers, it depends. Are you single and have no dependents (e.g. aging parents, younger siblings)? If so you can afford to make a switch although its unclear what you mean by environmental science. Do you mean activism? A specific 'hard' science involved in environmental science? Or-?