angel,
Please find a local alanon or naranon meeting. Go to them; get a sponsor. Learn to detach. You can love this person without getting sucked into the sickness. As you say, it's already taking a toll on you. It will get much, much worse if you do not learn to set boundaries, and take care of yourself first. The 12 steps of alanon/naranon will help you learn that. A sponsor will guide you on your way.
I look forward to hearing from you and knowing how you're doing. It's a difficult road you are traveling. Be sure to protect yourself.
Shalom!