For me, it first comes in as a wave of extreme irritability. I feel like I want to scream, punch the wall, break something; when I feel it coming on, I lock myself away, I move to a private place (ie. my bedroom, a bathroom stall, my car). I breathing starts to quicken, my legs are bouncing, I begin biting my nails, or clenching my hands into fists...sometimes, I dig my nails into my skin. My stomach begins to burn like you would not believe, I feel nauseated, like I am about to pop. And when I get to the point to where it feels like I am about to pass out, I cry...and I mean CRY. After that, it's gone, like nothing happened.