THIS IS NOT A DIAGNOSIS, but it sounds like you are suffering from a condition called periodontitis. This is a disease of gums and the tissue surrounding the teeth. Don't worry, it's entirely treatable. If confirmed by your dentist, you will need your teeth to be professionally cleaned (scaling). In the meantime use warm salt water to rinse out your mouth after every meal.
Next Steps
Please visit your dentist for proper diagnosis and treatment.
Health Tips
In the meantime use warm salt water to rinse out your mouth after every meal.