I take 1 Omeprazole pill a day (like Prilosec). But I was still having some problems. Then I read from another poster and some homeopathic websites that having 1-2 tablespoons of apple cider vinegar twice a day (best 30 min before a meal) helps the stomach acids do their job correctly. I don't know how it works, but it's amazing. Just on prilosec I was still having some discomfort. When I started taking the ACV, it got so much better very quickly. It's been a lifesaver for me.
Never had a problem before Mirena started acting up, but what else is new :) hopefully my stomach will heal eventually and go back to normal! Good luck!