In addition to seeing a headache specialist and doing everything Nancy suggested, you also might want to make sure to ask for an MRI and maybe even a lumbar puncture if you haven't had one already.
I was in a car accident 3 years ago where I was rear ended and whiplashed. Before this, I had episodic migraine, about 1-2 migraines per month. I didn't like strong sunlight, but I was fine in normal lighting conditions. After the accident, I slowly worsened, and 3 months later, I suddenly turned into chronic migraine girl, a migraine nearly every day, a brain that was suddenly pissed off by sound, light (so light sensitive that even a brief exposure to artificial light triggered a migraine everytime), foods I'd eaten my entire life with no trouble, weather changes, eyestrain.... it was like a switch flipped. My brain was pissed off by EVERYTHING and I just slowly deteriorated more and more over the course of the past three years. We can't eat off our plates or use real forks because the sound of fork vs. plate is so painful. We use paper and plastic utensils now.
I have had multiple doctors not know what to do with me. Accuse me of making it up. FINALLY a wonderful specialist for sound sensitivity recommended a lumbar puncture and do you know what they discovered? My intracranial pressure is too low, which could have been caused by the whiplash causing a leak, and could be making my brain constantly pissed off and prone to migraine. As soon as I started sleeping on one thin pillow, drinking ridiculous amounts of water, and lying flat for several hours during the day (so my brain got fluid), my migraines drastically decreased,.and my sensitivities immediately improved. It was shocking. Now we're working on finding/patching the leak so I can hopefully have a less pissed off brain (I know I will always have migraine, but removing this major trigger will surely help) and make some progress in a good direction towards getting better.
Anyway, my advice is if you were in a car accident and suddenly got sick, make sure your intracranial pressure isn't an issue. It can really screw thigns up.