If you have never swam before, do you plan to swim into a body of water while drugged? jump into one? I don't know how you'd plan to lose consciousness while trying to drown too. In general drowning experiences are quite awful, and the brain might wake you up too. There was someone here who went deep into the ocean with drugs and alcohol to try to do what you are saying, he did die, but of course couldn't report on if it really worked to lessen the pain and stress. So I can't really recommend that method, sorry you've been brought to consider it, don't know your situation, but I hope it gets easier for you in any way. Big hugs <3