You do not automatially get any kind of implied status just for applying for PR. If you applied for PR under spousal sponsorship inland and applied for an open work permit at the same time, you would have implied status.
If you applied under spousal sponsorship inland and did not apply for a work permit at the same time but you have your first stage approval already, you can apply for the open work permit now.
If you applied under other family sponsorship or spousal outland, you are not eligible for an open work permit along with that.
If that is the case, you could ask your employer to apply for an LMO for you so you can apply for a work permit based on that before your current work permit expires. If you do that, you would have implied status as long as you can apply for the new work permit before yours expires. Even if the employer applies for the LMO and hasn't gotten it yet, you can apply for concurrent processing once your work permit is 2 weeks away from expiring.
If the employer will not apply for an LMO for you or can't get one, you would have to stop working when your work permit expires. After your work permit expires, you would be out of status and would have a 3 month grace period to either restore your status or leave. If your PR hasn't come through by then, you would have to either apply to restore your status to visitor or leave Canada.
