You have ten days to leave the country from the last day. You can also take the position that you have PERM pending to stay in the country. Unfortunately your perm is based on your job. Normally when the company notifies USCIS, your perm and H-1B will be revoked at the same time. So that is a very risky position. Go to see an immigration attorney or call your former university supervisor to see if you can get a transition job...