Re: SSRI drugs rejected by body.
Sounds like you need consultation with a decent neurologist.
I developed a migraine condition very suddenly BEFORE I was treated for depression with medication, but was prescribed a combination of Depakote and SSRI medication, and later tried Neurontin with various SSRI's, which was fairly successful.
I also used a few "rescue" medications for migraine during that time, such as Migranal and Maxalt.
Fortunately, after a couple of years, the headaches have mostly vanished.
Just a hunch, but I'm suspicious about SSRI's causing your headaches. Not that SSRI's are great, or don't cause nasty side effects sometimes, but because certain migraine conditions can come on very suddenly and be very persistent.
Supplements I used to aid with Migraine were feverfew and capsaicin. Lavendar compresses helped a lot too.
The only other medication that helped with depression besides SSRI's was Lithium, although it was only temporary. I understand there are Lithium supplements that supposedly help people too.