What were your initial symptoms prior to your first test? Did you do antibiotics the first time? My GI Dr said GERD is not a symptom of h pylori. Both my parents take prilosec and still get heartburn on occasions. They both are h pylori negative after endoscopic biopsy. My main symptoms were gnawing, constant hunger type pains, growling belly, and loss of appetite. That all went away after the third day of treatment. I'm on day 9 now, 5 more to go. Do you take probiotics? Dr told me to continue taking them a month after treatment ends. It gets your belly back in order and helps with digestion and acid reflux.
I still have had heartburn and indigestion for years after h pylori treatment. My dr declined to retest me. So I have a new dr now and she said h pylori has become increasingly resistant to antibiotics and this is consistent with my research.
I would strongly suggest you try mastic gum extract along with lifestyle and dietary changes. Also, taking a substantial dosage of hcl betaine before high protein meals helps a lot.
Melatonin has also been proven to increase your chances of effective treatment when taken in combo with the antibiotic therapy. You could also try it by itself. I am awaiting a new test for h pylori after six years of gerd. I refuse to take antibiotics because I have researched more effective ways to deal with resistant h pylori.