Baybaysmom I am not sure if this is helpful but I will give you the benefit of my personal experience. At 73 I am a bit older than you but was suffering continuous Heartburn. Around 2000 my doctor put me on 30 mg Zoton tablets and for the last 12 or so years life has been a breeze. I take 1 per day straight after breakfast, and the only time (rarely) I get a bit of heartburn, is after too many reds.
Tums and Maalox are typically the first line over-the-counter medications you can try to relieve heartburn while pregnant. You may find the liquid to be more effective than the tablets as the liquid can also coat your esophagus (between your throat and stomach). Always be certain to inform your doctor of any medications you take (prescription and over-the-counter), and if these treatments have not been effective you should contact your doctor to review next steps. There are many prescription and over-the-counter products available, and some with the same ingredients. Your doctor can help you decide which is right for you.
There are many other practical steps you can take to avoid heartburn, such as eating frequent small meals vs large meals; eating slowly; and avoiding eating certain foods that are known to trigger your heartburn. Try to avoid laying down after eating, and when laying down, try to keep the head of your bed higher than the foot of your bed.