I had very atypical symptoms: chronic coughing, gunk in the throat, sinus infections, lung infections, ear infections, pneumonia, dental problems (from acid decaying it), loss of voice (sometimes for weeks), asthma attacks, almost blacking out, and occasional heartburn.
The mega doses happened over time. I started out with tums, then 40mg nexium at supper time, then 40 mg added in the morning, and then 300mg zantac at bedtime. After three years of that dose it stopped working.
After surgery I have to take an occasional tums, maybe two a week. It's been 14 months for me today.