Personal Attack!

This happened to my girlfriend the other night. She was walking up the steps to go to the bathroom and I heard a loud bang. I turned around, because I was on the computer, to see her laying forward on the stairs. I asked her what happened and she told me that she could not move her feet, she felt like she was paralyzed and then something behind her pushed her real hard up the steps. After she got up, she continued to the bathroom. While she was in the bathroom, I heard her crying. She came out saying that she couldn't breathe and it felt as if she was choking. I brought her downstairs and sat her in front of the AC. Our daughters were worked up & youngest crying and our son was going to call 911. I told him no and proceeded to tell her to take slow deep breaths and relax. After all was calmed down, she insisted on what she told me while this was happening.