How do I know if what was done to me was medical malpractice?

I have a diagnosed chronic illness of my nervous system, that causes every organ in my body to not function correctly, and my automatic functions to not work at times. I go to the hospital often because of it. I recently had an ablation on my heart, and went in to get an x-ray of my chest and an EKG on my heart because my pulse kept shifting around erratically, bradycardia, normal, and tachycardia and I was having a hard time breathing. I was very cool calm and collected. The doctor wanted me to walk so she could see my pulse, and during walking my pulse was normal, so I am assuming that she did not believe me after that, even though I had a supply of videos, plus a diagnosis of this happening. She said she was going to give me saline, even though I was just there for an x-ray and EKG. I told her politely that I already had 10 bottles of water and a bunch of salt and last time I had saline after being fully hydrated it made me very sick and puffy. She interrupted me while I was trying to explain to her what dysautonomia is and why I can't have saline right now, and was very agitated telling me that she’s the doctor and knows everything and I was trying to calm her down while she was going off on me for refusing saline, and I asked, "am I supposed to go home then because I can't have saline right now?" She said yes and stomped off to grab discharge papers. I was afraid at this point, which caused me to have a PTSD- like attack because I do have health anxiety dealing with my illness, especially with no help. I am so sweet all the time, and I couldn't understand this treatment. I asked her why she is refusing to test me and I got nothing back. I came to the nurse station and asked to speak with the staff manager, and she yelled out across the room, "I am the manager" while she wiggled her hips. I went back to my bed and thought, and started crying. The crying turned into a full-blown PTSD attack, and I kept going out in the hall crying and hyperventilating.