Your options are pretty limited.
You must have an approved LMIA in order to convert your status to a closed work permit and continue working. If your LMIA was just submitted now, it's extremely unlikely the LMIA will be approved in time (processing times are 2-4 months typically). If you don't have an approved LMIA in time, then you will need to apply to change your status to visitor before your PGWP expires and then stop working as soon as PGWP expires. Once you have an approved LMIA, you can then apply for a closed work permit and start working again once the closed work permit is approved.
If you have applied for PR and your application has been accepted as complete - then you may be able to apply for a Bridging Open Work Permit. Have you applied for PR?