Crossed out circle at boot up. Recovery not work. Help!

Hey! 1st received the dreaded crossed out circle icon this morning. Proceeded to shut down but wouldn’t immediately reboot. 8 hrs later, I try again & there are signs of life but the crossed out circle reappears. Command plus R resulted in error msg -2003F. I don’t see this error message listed in FAQs. What does it mea? Is my laptop gone for good?