Amy,
I have had migraines since the 3rd grade. They became really chronic and dibilitating in my 30's and 40's. (I am now 49). I had almost all your symptoms and I was diagnosed with PFO. You can google PFO and migraines and see what it is. My Dr. told me that 30% of the population has this and 50% of all chronic migraine sufferers have it. They tested me by TEE with bubble study and I had it. After suffering with migraines so severely I was glad they had found what was causing it. I had my PFO repaired 9/29/09 and I haven't had a migraine since. I am off all my migraine prevention meds and living a normal life. My Cardiologist and some of the web sites say that PFO symptoms such as migraines get worse in the 4th decade of your life.
Just a thought and you can ask your Neurologist about it. PFO can cause a full blown stroke and TIA's which are mini strokes.
No more migraines