Suggest Treatment For Chronic Migraines

I have had chronic migraines and Cluster headaches for 20 years. I have tried chiropractors, acupuncture, Botox, physical Therapy, several ergots, triptans, antidepressants, and anticonvulsants. I have finally found a wonderful neurologist who specializes in migraines and cluster headaches. He has me taking Effexor 150mg, Keppra 500mg twice daily, Tizanidine 2mg twice daily, Zofran 8mg as needed, Nartriptan 2.5mg as needed, and Dexamethasone 4mg only for emergencies. I was getting these migraines three out of four weeks. Now I am down to two weeks per month. I was on Migranol instead of Nartriptan, and it worked wonderfully. Unfortunately, my insurance, which gave me no problems last year, no longer want to pay for this. The doctor has since prescribed Nartriptan in its place. There are only 9 pills. They do not cover my whole month. The insurance will only cover 9 pills also. I LOVE my job as an accountant. I am now being told by my doctor I need to try not taking all nine pills and spread them out. I just cannot pick and choose which one I want to suffer through. The pain is unbearable and when I run out of pills I end up missing work. I cannot keep missing work because I do not have any sort of abortive medication left. What does a chronic migraine/cluster headache sufferer do when faced with this challenge? The Dexamethasone makes me very sick, heartburn, constipation and extreme weight gain. It is a double edge sword. I am desperate. I worked way too hard to achieve the success in my career to lose it to this. Please help!