Blair, my heart goes out to you. My daughter Erin was a sophomore this year who has been suffering from chronic migraines for the last 3 yrs. they too originally tried to treat as allergies and then sinus infections. The migraine diagnosis was a relief or so I thought. It seems that none of the prescription drugs that are supposed to help a migraine at onset or break the migraine when entrenched in it like you are work for her. Some even make it worse. She had the MRI, CAT scans and all were negative thank goodness. For a while she seemed to have a handle on it by having to keep a lot of balls in the air at once. Chiropractic, accupuncture, taking dairy out of her diet, keeping hydrated, eating regular meals, getting the right amount of sleep and Amitryptiline prescribed by her Neurologist. If she dropped even one of the balls it would bring on a Migraine. She learned how to function at school with a pain level up to a 6. When her monthly cycle came the migraines were worse and nothing helped that. At the beginning of this year in January things changed. She too started to get extreme jaw pain and was told she had TMJ. It seemed to intensify the migraines and things stated to go down hill. She became unable to focus at school and had to quit managing softball. She started to vomit daily, depression and then anxiety. She missed 25 of the last 40 days of school. She has been barely functional at best and nonfunctional most days for the last four months. She has had many weird symptoms and it seems like a new symptom each week worse then the last.
Long story short, after journaling all of her symtoms over the last 8 months it seems to point to liver disfunction due to Chronic Neurotoxic Syndrome.
Blair, have you ever had problems with you vision over the years?
Ask you Chiropractor if they have heard of a Visual Contrast Test. It is a quick visual test that can show if you have a build up of biotoxins which is affecting your liver functions. Google chronic neurotoxic syndrome or nonfunctioning liver and you will probably see a lot of the symptoms you have. Until Erin started to have weird raised red rashes on her upper arms, chest and upper back and chronic sweating while at rest, the liver was never considered as a root cause for the headaches.
I'm very sorry for your situation. My best recommendation is to try and journal your whole experience. By doing that and listing her symptoms chronologically, the puzzle became a bit clearer. Best of luck to you.