There may be another reason, aside from the overdose that your doctors won't want to prescribe any more narcotics. With the brain damage, the damage to your lungs, and the kidney failure, your body may not be able to tolerate the side effects from the narcotics any more.
As far as you taking any morphine that you have at home, after a month in the hospital, I'm pretty sure that your body has gone through withdrawal of the narcotics while you were there, and by taking it now, you are going to throw yourself back into withdrawal if you continue to take it.
I would strongly suggest that you don't take any more and get rid of what you do have at home instead of taking it. Contact your doctors and ask them what you can take for pain aside from the morphine. With all of your medical problems now, you don't want to make any more medical crisises for yourself.