Being forced to use harsh methods is understandable, I'm in a similar situation where I can't find more painless methods for the time being. Hanging, jumping, drowning, stabbing... But all of these harsh methods are both painful and risky, and they involve a lot of SI too which makes them harder to execute.
I hope you don't have to suffer from such methods, exsanguination sounds like it would require immense courage and would involve a lot of pain if I've understood it correctly :(
It's sad that a person can suffer to the point that such methods are their only escape. Hope you find peace in whatever you do, but I also hope your decision is well informed