We've talked on another thread about gastritis, but I'll just mention a couple of points here. Mine is most likely revved up by antibiotics. I try to avoid them, but sometimes you just can't.
Once I get started, though, it takes MONTHS to recover. Actually before my Nissen, it was so much worse due to reflux. Gastritis and esophagitis in tandem are no fun. The problem for me now is that minus the esophagitis I'm more tempted to ignore my symptoms and irritate my stomach further. It's just getting better, and I'll eat something irritating and I'm back to square one.
The problem with having a reactive stomach and a Nissen is that the wrap is created out of the stomach, and if the stomach is reactive, the wrap will be, too. My wrap is often irritated, which can be very uncomfortable.
I use Carafate suspension--a liquid form of Sucrafate. I find it incredibly helpful, as it coats the wrap nicely. I expect I'll be using Carafate forever, as I don't see any indication that my gastritis is going anywhere soon. I find liquid Maalox to be helpful as well.
I find that one of the most important things in healing gastritis is to stick to smooth food and avoid anything that stays rough in the stomach. Stomachs contract and grind the food as it digests, and anything rough or scratchy can really irritate. Smooth, no heat or spices...I think we're all different as to what we can tolerate. That's the strange thing with GI issues...we may have similar symptoms, but the details can vary greatly.
Good luck with getting your stomach better.