Ulcers can be a result of low stomach acid, so a proton-pump inhibitor is not going to be helpful in the long run. Adequate probiotics are also important in gut health.
Don't do anything sudden with the PPI, if you are already on it. I would suggest you try "supplementing" apple cider vinegar & probiotics to see how that improves any symptoms you are having. Avoid wheat & alcohol entirely.
I would think that in general, a paleo diet is good for gut health and so it would help for an ulcer. A GAPS-like diet (focusing on probiotics & bone broth) is great for gut health, especially when healing from something severe. Perhaps do some research into that?