Headaches for me were dehydration, I found a nice soak in the bath with an icy pole & bottle of water helped.

Sometimes you just need sleep too, good un-interupted sleep.

What you said about your blood sugar sounds like something worth looking into. maybe you are getting too many refined sugars and are getting headaches when coming off a sugar high and then you crave more sugar etc etc.

Try some low GI foods next time you want sugar, maybe oats for breafast??