Diagnosed with Collagenous Gastritis

I had an endoscopy/colonoscopy done on the 11th and my biopsy results came back negative for H. Pylori, but showed collagenous gastritis. Colonoscopy was clear, with no biopsies there. My symptoms are very odd in my opinion based off what I’ve read about this disease so far:

Adrenaline rush/heat rush/feeling of dread during or after eating
Panic attacks triggered by adrenaline rushes
Flare ups of epigastric/abdominal pain after eating
Heart palpitations
Extreme fatigue
Nausea/occasional vomiting
Unintended weight loss (132 down to 111 in a month)
Slow moving stool/frequent constipation
Severe neck and lower back (tailbone) pain
Dehydration
Fatty foods like steak and cheese trigger my adrenaline rushes/abdominal symptoms
Am able to eat bread with no symptoms
Talking to my PCP tomorrow about secondary testing for autoimmune diseases (my mother has Rheumatoid Arthritis but does not test positive on blood tests. I might have inherited this as I was tested for Celiac and Sjogren's - negative for both)

If anyone could give me some insight on how to manage this disease, I would really appreciate it. I’m scared for my health and I hate that this is so rare that I can’t find any of the answers I’m looking for. I know there are many who have had this with no answers for a number of years, I have dealt with the brunt of it since July and I feel scared all the time.
I am interested in any clinical trials current or upcoming as well if there are any.
Thank you for your time