please help.

i have been having trouble meeting my calorie requirements for the past few days (i usually have shot for 1800 cals, 110gr protein, 130gr fat, and 20-25 gr CHO, and for the past three days it has been closer to 1300 cals, 85 gr protein, 85 gr fat, and 15-20 gr CHO)

AND I HAVE KILLER HEADACHES. they get worse from noise, sudden movements, head turning, basically the longer i am awake the worse they get.

they are like the low-blood sugar headaches i used to get. and they are awful. they don't go away when i take excedrin, or drink more water, or lie down, or anything, and they are making me so irritable and mean! my babies and my husband are begging me to figure out the cause so i can stop the madness.

im getting plenty of sleep. and not eating frankenfoods (see my fitday link in sig). and not drinking alcoholic beverages (i never really have either, so its not like withdrawal.)

and i'm of the mind that most physical ailments are diet-linked. so that's where i'm starting first. if i call the local nurse, she'll tell me its my own fault for eating like a "freak" (read: Atkins) and the same goes for my nutritional and homeopathic books. the first things they tell you to avoid in every scenario are the building blocks of this WOE.

could this have to do with the lack of calories? or ovulation? (its approximately that stage in my cycle) can anyone offer any leads i can sniff out? something i've failed to consider perhaps? cause this sucks.