That is my exact problem. It started one year ago this November...I wish I could tell you it has gone away but it has not. At first I would get terrible panic attacks thinking I was going to stop breathing, but as time went on I got a little more confident that my breathing would not stop. My regimine now is I take 2 Zantac 1500 one in the morning and one at night plus Pepcid complete in between. I used to take the PPI's like Nexium but was having side effects. I also stay awya from Chocolate and the usual high acidic foods. Sometimes I feel like my throat is spasming so I take .5 of Klonopin (its like Xanax) to help with that.

It's really a lot of trial and error... some people have results on the PPI's like your taking, but it can take up to 6 months for it to go away...
I have a strong case and although it's more tolerable it's still not gone and the breathing is the worse part of it, I just wish I could go back to the day before it started and see waht I did wrong!

Good Luck and know you're not alone!