Acid Reflux

I have had acid reflux for years now and have kept it under control by takin 75mg Zantac one in morning and one in evening, I also had my gallbladder removed about 4 yrs ago, and I also have anxiety which is kept under control with xanax, but the problem is for the last few months my reflux has been getting worse and im taking several of the zantac thruout day, I eat dinner early and I still get it while Im asleep and wake with it...is this something I should be concerned about could there be something else going on??? Any advise is greatly appriciated..

Thanks