Hi, mild gastritis can feel extremely uncomfortable. Technically it's only serious if it continues on to develop ulcers or polyps.
Gastritis can be managed through medications like H2 blockers or Proton pump inhibitors (PPI). Your doctor will suggest a course of action. Most of the time PPI's are only meant to be taken a short period of time.
The best way to manage any pain and nausea is to change your diet. Stay away from fried and spicy (even if it's not hot it still may be spicy) foods. Eat lean meats and steamed vegetables. Stay away from coffee, tea and soda as well. Garlic, onions and tomatoes are also irritating to the stomach. Get some coconut water and stay hydrated with filtered water. Give your stomach time to heal.
Every person heals at a different rate, so there's no clear answer as to when you'll be able to eat normally again. Listen to your body when you eat. It'll let you know what's irritating.
I have acute gastritis and changing my diet helped with the pain, as well as taking a PPI. As of today I'm weaning off of the PPI as I've been on them for 4 weeks now.
Best of luck ! :-)
How are you doing now? Is your stomach better? Please let us know.