Help - I don't know what is going on!

I have been having these brutal "dizzy spell" type things going on. It always occurs 1st thing in the morning, and usually I am either half way through a smoke, or just finished my 1st smoke. I suddenly become extremely dizzy - and I get to the point of near fainting (usually collapse on the floor, but not totally pass out). I become incredibly sweaty and hot. My arms/face become covered in sweat. I become terrified and just try to breath and get myself in a cold place.

I have had 2 in the last two weeks but I have had them last month as well and the month before that. I have no idea what is going on - is it diet related?

I am confident it is not pregnancy, but not 100%. I also have an IUD if that helps...a copper one.

I am eating around 1300-1400 calories a day...losing about 1lb a week. Has anyone had this happen to them?