Immetrix injections limited by insurance company

I have suffered with intense migraines for 50 years (this year has been really bad). Been on many meds but immetrix injections always take the migraine away. I used to get 18 shots a month and for the past 2 years no matter how many letters my PCP sends to Health America, they will only allow 8 shots per month. I am so frustrated and always a nervous wreck worrying about running out. I almost always get mine around 2 or 3 am in the morning but sometimes get them early evening and they are the most intense and hardest to get rid of. I have gone over 11 hours in agony trying to conserve the shots, how sad when you know you have something to end all this pain in a matter of minutes but you can't take it! I hate insurance companies. Tried acupuncture to no avail and also chiropractor didn't work but so desparate thinking about trying that again because I have such pain in my neck (desk job with lots of stress). Anyone have any thoughts?