Try mylanta, it's on my list of safe medicines from dr. And it helps me so much more than tums. Stupid chalk pieces do nothing when I feel like I've got globs of lava rising out of my stomach and bursting in my throat lol mylanta calms it right away.
I am taking a pill for it as well as tums. Sometimes they don't help at all sometimes they help a lot. When they don't help, I drink store bought chocolate milk. The reason I drink chocolate milk is because both chocolate and milk are more basic than acidic on the PH scale. Also, smaller meals and laying on your left side when laying down, because on your left side your stomach is lower than your esophagus helping the stomach acid stay where it should be.
I'm 21weeks, and I've noticed mine is slowly getting worse, it feels like even drinking water causes or makes heartburn worse!! :/