I got into bed tonight and was laying on my stomach and I started to get a sharp pain in my central lower abdomen, I sat up and felt nauseous and had very short breaths and felt like I had forgotten to breathe properly. My hands became a little shaky and body tense and a little twitchy. Also, I'm so bloated it looks like I'm pregnant, my stomach is hard and big when I stand up. I haven't been for a "number 2" since last night and I'm currently on my period. What could this be and/or what is causing this!