I had indigestion from 15 weeks through to term and tried a million things. I used bicarb soda also, as my best friends mother told me that is what they used back in the 50s and 60s. I tried eliminating lots of things from my diet to see what was doing it and in the end, about 3 weeks before I delivered, I found it was eating bread and water at the same time as it seemed to mix together and blow up like a sponge in my stomach. So I started eating yeast free bread and not drinking when I ate and it was much better. But what causes it can vary for everyone so maybe see if something in particular is causing it. Also they say to eat your big meal at lunchtime and have a smaller meal in the evening so it has a chance to digest better. It is a horrible thing so I hope you can treat it.