I Switched From Dexilant To Zantec. I Have Been Taking

I switched from Dexilant to Zantec. I have been taking Dexilant for more than 10 years with no ill effects and complete relief. But recent links to dementia made me switch on doctor's suggestion. However, Zantec does not seem to give me relief and also I feel increase in anxiety that I did not have before. I have only been taking Zantec a week, however. Advice?