Chronic duodenitis and gastritis.

I am an anxious person and i take one of ssri med since 7 yrs for anxiety and depression . Paroxetine 10 mg dailly. But since 6 months i am suffering from heartburn even from water .which starts post food 2 hrs like this. Went to my psychiatrist he changed my med to fluoxetine 20 mg bcs may be using of paroxetine for 7 yrs is the cause for heartburn. But symptoms of stomach after changing to fluoxetine get worsed. I was admitted in hospital and endoscopy done with colonoscopy. The result of biopsies taken : peptic duodenitis and chronic gastritis plus IBS in colon. I want ur opinoin does paroxetine cause what i have ? Bcs now i am on mirtazapine 15 mg but not stable crying suddenly and cause me grogginess plus sleeping too much and not hit my palpitation same like paroxetine did. Note :acidity is reduced now than before 4 months . And i am off paroxetine 1 month cani return my paroxetine or it will worse the duodenitis? What should i take for chronic gastritis and peptic duodenitis?