its certainly possible, my cousin had H pylori infection for 3 years before even going to doctor, he had constant nausea, acid reflux, stomach ache, heartburn like symptoms and vomiting, these would come and go for long bouts.
so its certainly possible, discuss with your doctor but you really need to come off ppi before performing the tests unless its endoscopic biopsy test.
honestly I am going through nightmare myself with gastritis and its medication, i basically have not been able to stand or sit for more than 10min at a time for about 5 of the 6 months i have had gastritis, it has made my life a living hell only laying down in bed constantly and in pain 24-7 and recently i seem to have gotten more worse.
you need to be strong, just thank god you can stand and sit, i can't even do that and the doctors are clueless about what is happening to me and i basically just hoping my body recovers by itself. PPi and gastritis have ruined my life, one or the other or both has fried the nerves in my stomach, my take its that it caused my stomach to inflame and when it pressed against my ribcage it causes me nerve pain somehow. If i stand longer than 10min, my stomach spews acid up my osophagus, which is painful as hell.
sorry for the long story but don't be put off and stay strong you will be fine, there are many worser than us out there, so always be grateful and you will be just fine.
good luck with everything.