How can I prevent gastritis, I awake in the middle of the night with an acid that takes my breath away & my nose & stomach w/ severe reflux for 1hr +?

Esophageal reflux. Rather then gastritis, this sounds like reflux. The most powerful meds for this are proton pump inhibitors (ppi). Over the counter antacids and histamine blockers are also useful. Lifestyle modifications such as raising the head of the bed when you sleep, decreasing fat in your diet, and avoid lying down for 3 hours after eating. Nicotine, caffeine and alcohol all worsen reflux.
Gastritis. Many things can irritate the stomach alcohol, caffeine , nicotine, mint, fat and spicy food among others. You don't give your medical conditions or medications that you take, any. All these can play a role.