In which case you have no hope of getting approved any time soon. If you wish to go to school, you can't do it in this country on an F1, sorry.
So your options are:
1. If you want to continue living in the US, stick to your job or use AC21 if you want to change jobs. This will considerably delay your school plans.
2. If going to school is a higher priority, forget the US and look for a school elsewhere.
3. If you want to live in the US AND go to school, consider going to school part time. This will have the restriction that you'll need to find a job/school in the same city that you have the school/job, for physical reasons, obviously.
4. There is another, riskier, option: just go to school full time on AOS. As long as your employer doesn't withdraw the 140, you're fine. Finish school, get a job in a new field using EAD and pursue a new career. If there is no RFE on your 485 and you get approved in a few years, continue in the new line. This could be considered fraud by the USCIS and is not a recommended option, but *could* work out, depending on how your stars are aligned...
Or else, for a less risky option, once your GC is approved, come back to the sponsoring employer, work in the job listed for six months or so and go back to whatever you were doing. This is a better option if the employer is supportive and things could work out for you.