OPT is denied if your application is received after the date of your graduation, or after the date of your degree completion. In such case you get a denial notice stating that you have 60 days either to change your status or to leave the country.  The best way to stay in status is to go back to school and apply for a new I-20 within that 60-day window. Once you get an I-20 you can work to change your status from F1 to H-1B with the help of CPT and a job offer from employer ready to sponsor H-1B.

GoodLuck