This happens when I'm about 2-3 days late for my period. As soon as it starts, maybe a few minutes after. I'll feel hot and start to sweat, have to use the restroom, stomach ache, severe cramps, dizzy, naseous, sometimes I'll actually throw up. I went to the Dr a few months ago, they did some blood tests and everything came back negative. Does anyone know what this could be? It's been happening for about 3 years now.