I have had awful acid-reflux for about 5 years now (hilariously enough they gave me a pregnancy test because the worst system was a milk-curdling sensation in my stomach).
I would first suggest maybe cutting down on the acidity in your regular diet, caffeine is a big agitator, as is anything with a lot of citrus, excessive fat, grease, anything tomato based, taking the fun out of things eh!? Perhaps you could also ask your doc about a once-a-day acid reflux pill, something like Nexium (which I believed I've read is okay to take during preggos?). Laying down after eating can cause issues, as eating too much.
In the meantime, I know Maalox, Mylanta, Rolaids, Tums can be backups & are listed as baby-safe. Hope this helps a little.