What options do I have if my insurance doesn't cover a medical need for gastric bypass from a sleeve?

I have the sleeve done 5 years ago and have done very well with losing the weight and keeping it off but I have developed acid reflux so bad that I have been off and on liquids for the past 3 years and for the past 2 weeks I have no voice due to the acid reflux. I cough up blood, and faint. The doctor who did my surgery told me he has to change my sleeve to the gastric bypass but my insurance won't cover it and I am about to lose my job because I have be unable to speak for 2 weeks. Please help