What Causes Recurring Episodes Of Acid Reflux Despite Taking Nexium?

I have acid reflux and just stopped taking nexium. I am on nothing now. Woke up with what felt like acid or vomit in the back of my throat. Took antacids for temporary relief. This a.m. I hadn't eaten yet and the symptoms returned. Now seems to be getting worse. Also the taste of my burps is disgusting. Taking antacids every hour now. My concern is that this is more than acid reflux.