Do I have grounds for a medical negligence lawsuit?

A few months ago, I was in extreme pain in the left side of my body. I went to the local ER and they misdiagnosed me with a strained back after doing no testing or examinations on me, they gave me a muscle relaxer and sent me home. The following afternoon, the pain intensified so I went back to the same ER and they performed a chest x-ray and took blood work. While waiting I asked a nurse for a blanket because I was cold. She seem noticeably annoyed. I had asked and proceeded to throw a blanket at me from the doorway, a good 10 feet away, and it hit me very hard on my chest. The doctor then advised the same nurse to give me something for my pain before he exited the room. The nurse replied that I could wait because she was busy doing another task, blatantly ignoring the doctors order. She made me wait a very long time for medication to relieve the pain. I was informed that this time, I had kidney stones and discharged me again. This time discharging me although I still had a fever of 103F. The following day, the pain was still severe, so I contacted my sister who works for a doctor’s office. She then contacted her boss who is a surgeon and he, after hearing my symptoms, immediately direct admitted me through the same ER. I was told that if I had not been admitted I would have been dead within 24 hours due to sepsis in the blood. The failure of the hospital to correctly diagnose me and discharge me without administering the proper tests resulted in diminished lung capacity in my left lung, endocarditis of the heart, loss of my job, and now being dependent on medications for the rest of my life. It has also greatly inhibited my quality of life due to my health issues. It has also caused severe anxiety and depression. The ER staff treated me as if I was a "drug seeker", failing to take my pain or symptoms seriously, let alone treating them.