Oh man, that stinks, and I totally feel your pain....Literally!
I'm actually on prescription meds for GERD which is called Dexilant...it helps, but technically I'm not supposed to be on it, 'forever', just for a few mos, and the acid should magically disappear, and I'll never have this problem again...Wrong!!!
I probably need to visit a GI dr. to have something that does regulate me completely (not just temporarily fixes the issue), and he/she should also check out to make sure there's no damage to the esophagus.
But some advice, Tums definitely helps me in a time of emergency need! And I sometimes have to sleep with my pillow upright, which is not the most comfortable (had to do it practically the entire time I was PG with DD!), but it does help!
Other advice is to avoid foods...chocolate, soda, acidic sauces/salsas, etc....
Good luck..if it doesn't get better, definitely make a dr. appt. as you might need something stronger!