Body Care Now To Prevent Future Problems

I have been on Omeprazole for a while now but my energy levels are really low and I have now been diagnosed with TAT (tired all the time).  I saw a nutritionist and she said thought taht the omeprazole may be part of the problem. she also said that high stomach acid was very rare and tht it is actally low stomach acid that is usually the problem.  I am a bit worried about coming off my medication and wondered if there was a protocol which you could advise me to follow. I never had GERD to start with only complicationswith my stomach after NSAID'sand then I wasdiagnpsed with a hiatus Hernia but that was asymptomatic anyway. Any help would be great? Also is there atest which can definitively measure Stomach acid? The nutritionist mentioned a gastro string tets but it sounded a bt unpleasant?? Thanks Dawn