I have headache sore body and fever, fine during the day just starts at night for the past 3 days what can this be

Do you have a rash?: There are many possibilities but I'd worry about tick borne illness if you've been in exposed areas/tall grass etc. Mosquito borne illness also possible. So is flu. Or Covid19. Many possibilities. Are any of your friends ill? Do you have a cough? Are you short of breath? If you're not getting better, you'll need to be seen and examined. If insect related, you may require an antibiotic.