There can be a lot of reasons for the bleeding.
You might have plaque or calculus which is leading to the bleeding , scaling from a dentist can help in it.
Or there can be some health related issues for which you might have to get a blood test done.
But first and foremost is consulting a dentist do it first and then move on to other factors
Next Steps
Consult a dentist online/offline
Health Tips
Brush twice daily and do warm saline rinses