How do I pursue a case in which I feel Medical negligence has occurred in a hospital stay? A nurse at the Hospital said I have a case.

I had a procedure done at a hospital, which was very invasive, after already having lung cancer removed that week. I had a second surgery after the first one that week, and still no relief. My lungs were filling up with fluids and I was dieing. They went through my mouth to suck out the fluids I was drowning on. I asked to be completely put out and it was promised by my doctor that I would never remember it or wake up at all. I woke up and was paralyzed and none of the Doctors team realized I was awake. When they finally did, all they told me to do relax, but I couldn''t because I was gagging on a massive tube in my throat. Now I am experiencing horrible panic attacks,anxiety, which I have never endured and when I go to sleep at night it''s all I think and dream about. I feel I may need Medical Therapy/Counseling. I am also fearful I may now have P.T.S.D. I filed a grievance at the hospital. I want to know if I have a case.