I also started getting migraines at puberty and they became more frequent and more severe in my thirties.  Also, my name is Karen!

I used to be able to fall asleep and awake without the headache.  But as they became more severe I took Amerge (like Immitrex) to get over it. They became more frequent and I took more Amerge, only to get more headaches because of the rebound factor.  I went to neurologists, an ear/nose/throat doctor and had sinus surgery, after also getting tested by an allergist.  I quit my job over this, thinking it was stress, but the headaches kept coming.  I was on Dr. Atkin's diet, which excludes most carbs (including bread, etc. which is not gluten-free).  I noticed during that time I had fewer headaches. So the answer was simple: it was wheat (or gluten) in foods.  It was that simple and not one of the doctors ever suggested it as a problem.  For me, it sets off an inflammation which effects a migraine and I usually have some stuffiness in my nose and sinuses, which led me to a sinus doctor.

Anyone can do a simple trial to determine if gluten initiates their migraines.  Eliminate gluten from your diet for 2 to 4 weeks.  That means no bread, bagels, chips with wheat, pizza and all the other things made from wheat, rye, barley.  Don't eat steel-cut oats or "modified food starch" which is used as a thickener in foods like soup or puddings.

Gluten affects me according to my menstrual cycle.  There are some days that I CAN eat gluten products, but I never know which days those are.  The week prior to a period is the worse.  Even though I wasn't getting periods and have since had a hysterectomy, my brain still sends out "cycle" signals and I still can get the migraines.

I continue to eat the "bad" foods, even though I can buy special gluten-free products.  Sometimes it's a matter of wanting a cake dessert at a friend's home or restaurant.  The way I get around the headache is to have some coffee with a gluten food.  The coffee constricts the blood vessels and that seems to prevent the headache.  I am careful how much of the "bad" (gluten) food I eat.  Still, if a headache starts, I bite off 1/4 of my 5mg Amerge migraine medication, and it averts a larger migraine.  Because some of these migraines are very slow in starting (maybe over hours) the migraine might not appear to be connected to eating a wheat(gluten) item.  I didn't want to believe that I couldn't eat wheat so I tested it MANY times and continued to suffer many more times.  It's been almost 5 years since I connected gluten with migraines and I'm now in control of my headaches.  Be sure to read package labels though, as once Doritos were made with wheat.  I woke up at 2am with a migraine from Doritos at 9pm. 

Other tips: avoid alchoholic drinks, as they are made from rye, wheat, etc.  Somehow they must react in the same way, as I get migraines from these.  The more that we are told to eat more whole wheat products, and I did, is when my headaches became more frequent too!

Good luck.