I think I just got PTSD from work emergencies?

My client had 3 life threatening emergencies within 2 hours last night. After that, whenever she made a noise, I thought she would have another seizure and tried to rush over there, but she just coughed. Then I was outside w/her family and thought I heard her screaming for help and panicked, but she was fine. I had 2 startle reponses driving home. My roommate is home, and somehow made a noise that my client would made, and my heart started racing until I realized everything was fine. I keep thinking I'm hearing my phone ring, my computer do things, and for some reason, I think about her seizures. They were all really bad and the confusion and seizures lasted over 15 min each. I'm afraid I'll be there and she'll die and that I could have prevented it. Is this PTSD? It happened on the job, but I was told what i was getting into. What do I do?