I have some Gastritis questions

[Scubadoo33]

So, historically I have had issues with my stomach when really stressed out or when my depression/anxiety get really bad.  Well,  lately that stress level has been at its all time worst, and my depression has been pretty epic.  My back went out the week before thanksgiving (USA) and I've been having treatments for that,  including an epidural a week and a half ago. On black Friday,  I wasnt feeling so well in my stomach/ abdomen. I actually didn't overdue it at thanksgiving (first time i can really say that) bc I was really in pain from my back and just wasnt interested. I didn't eat much on the Friday to let my stomach calm down.  Well,  that Saturday and Sunday the combo of back pain and abdominal pain was horrendous.  
Monday evening I told my husband that I needed to go to the hospital.  The reason was 2 fold. I needed to get my stomach checked out,  and the pain had literally taken me to the end of my rope.  I needed to go to crisis.
In the er, they have me some pain medicine,  and it took 2 doses of iv pain meds to calm down my stomach. They did a ct with contrast and it was inconclusive. The er doc said it was likely either gastritis or an ulcer. I haven't eaten much at all since black Friday. I've probably ingested maybe 11000 calories in total.  Ive lost 17 pounds since the onset. Its horrible.  My skin is uber dry and breaking down,  and sometimes I wake in the middle of the night either retching  or vomiting for hours.
I had an endoscopy today and the doctor said that I have moderate to severe gastritis,  but no ulcers.  He took biopsy samples to be analyzed for H Pylori. He said I should have the results by the end of the week and wants me to continue on my nexium 40mg 2x day and reschedule for 3-4 weeks.  
I do not use anti inflammatory drugs as I take blood thinners,  and, ironically,the risk of an ulcer is too great.

I'm just worried that if this isn't an H Pylori infection,  there's not going to be any relief over the next 4 weeks. I won't be able to handle it. Seriously,  I won't be able to.

What other causes have you seen/experienced for Gastritis?

I also get that pulse in my abdomen thing when laying down.  I had the ct scan in the er, so I assume they would have seen am aortic aneurysm then???? Is a ct scan with contrast the definitive test for that?

Thanks all.