Food on period?

On my period I crave foods like crazy. But my problem is I can never keep any foods down on my period! I had an IUD for 3 years and didn't have a period. I'm back on the pill and have been getting a period for 3 months now, but every time I have my period I can't keep any food down for the entire 5-7 days I have my period. I've tried plain diets, liquid diets. Nothing. I can't keep ANYTHING down. But as soon as my period is over I'm fine. Does anyone else have this problem? Or ever had this problem? I have a doctors appointment in a few hours to speak with her about it, I was just wondering other's experiences with this.