Worry

Today I went into the emergency department at a hospital close to my home( not the one I usually go to) because I am having contractions. some were so severe that I puked. anyways, after they drew blood and had an ultra sound, the ultra sound said I had retroplacental uterine contractions and I was curious as to what this means? I want to know what retroplacental uterine contractions are and how serious this is? The hospital I went to, I was seing by er doctors not ob/gyn doctors and the er doctors sended me home with not treatment and I am now home worry sick to my mind and still in pain/ Please if any of you know what this means, please, please let me know. I am scare out of my mind because I am not even 20 weeks yet and I do not want anything to happen to my baby. I am sad and want to cry my heart out!