Newbie, losing my mind with anxiety

Hey all,
I’ve been stalking the site/facebook page/forums for a little while now, and I’m finally breaking down and writing something because I just can’t be silent any longer.
I am on my 3rd LOA in as many years from a call center job, due to migraines. Currently, my treatment is overseen by my pcp as my headache specialist dumped me a year ago because I wanted to start a family with my husband. She absolutely refused treat me while I was off birth control. I was completely left in the lurch, but at the time I felt OK because my PCP said she would manage my Topamax prescription and help out where she could with the migraines while I tried to get pregnant.
Well, here I am a year later, still not pregnant (now seeking infertility treatment), and my migraines are out of control. Today, I’m in that part of the country caught up in the nor’easter and after I post this I am going to take a fioricet, then curl up on my couch in complete darkness to try to get some relief.
This week things have just come to head, as my short-term disability has yet to be approved and I’ve been out of work for a month now. My disability rep says they don’t have an adequate listing of my symptoms to deem my claim as medically necessary, and my pcp won’t write any additional notes because I wasn’t reporting in to her every time I had a migraine. I feel really ripped off. She agreed to write the paperwork for the LOA, so obviously she believes in my condition, but won’t expound on my symptoms? Secondly, I have a migraine nearly every day, am I supposed to call and badger her office staff to say, “hey, I have a migraine, here’s a list of my symptoms, please pass it along to the doc.”? If so, when she took over my care for my migraines, she never made that clear to me. Like most people, I only seek additional medical care if I can’t control my migraine at home. (though they do know me by name/condition at my local immediate care center, “here for toradol, Zofran and iv fluids again?”)
Also! (and finally) I have an appointment to see a new headache specialist this coming Wednesday. I am terrified. My last headache specialist believed that people with headaches/migraines had no reason to stop working. So I’m afraid by going to this new place on Wednesday, I’m just going to get more of the same. Unless/Until I can get these migraines under better control I don’t see how I can return to my work environment with bright fluorescent lighting, sitting in front of computer all day, in a loud area with a headset attached as I try to take calls and manage people’s finances.
The place I’m going to is coming highly recommended by the doctor that first diagnosed with me migraines, back in the day. It’s also a headache center started and maintained by a fellow migraineur, and author of a book about migraines. But I can’t find any solid reviews about the place or level of care, and that’s also leading to my anxiety.
Does anyone have any thoughts about what questions I should ask at the appt. on Wednesday? How I should handle my pcp’s office and/or the disability rep?