EGD today showed severe gastritis & slow motility. Zero food x13 days. Severe N/V. down 22lbs in 3 months no constipation. Can gastritis cause this?

Your system is out o. As far as the gastritis and slow motility your doctor must tell you what to do. No food at all for 13 days will cause you to lose a bunch of weight. Sounds like you need a good trial of antacid medical treatment. So kits time to quit treating yourself and talk to your doc.