The fact that you have problem with tonsil stone for a long time tells me that the bleeding might be caused by the stones coming out.
You said you were 15 years old when you started having this problem. How old are you now?
Do your tonsils ever swell? I don’t know if you had a doctor look them up, but it might be a good idea to get them out. And I mean both, tonsils stones and tonsils.
For now I would just suggest that you use some mouthwash and try with antibacterial medication. You should be good in a few days. But if this problem reappears again, you will need more effective treatment.