Stomach Pain

So I haven't eaten as much as I normally would today and I've still got like a week until my period is supposed to come, but I'm get really painful stomach pains right below my belly button. It's feels worst than any cramps I've ever had (one time I was lying in bed with a hot water bottle and I was still screaming at my dad cause we didn't have any Advil). The only thing that seems to me helping is lying down with my knees on my chest to put pressure on the spot but even that isn't doing much. Any idea what it might be? Please answer quickly!!!