-You may negotaite with your employer to extend your employment until the end of may so that you can file your I-485. Then, as long as your employer does not withdraw the I-140 for 180 days, your I-485 will be safe if you can find a job in the same/similar area based on AC21. So, talk to your employer about it to save your GC application and ask them to help you.
能合法停留等待多長時間?
-You can stay legally until your current I-94 expires, but you will be out of status after you lose your job. Of course, if you file your I-485 before you are laid off, you will be OK (see above answer).
萬分感謝好心人解答!!