I also got something prescribed to me by my doc, if it's really bad ask your doc for something, I haven't had heartburn since I've been taking it and I'm now 38 weeks!
I popped tums like it was my job when I had my second trimester heartburn. Good news is it went away in my third trimester!
I was sick of popping tums like candy so my doc finally recommended zantac and it really did help.
Zantac 150.... Buy it... It was my lifesaver.
I was that way with my first ..I had to talk to my doctor and he gave me a nausea medicine and told me to take that with tums and if the tums didn't work he'd prescribe zantac or something ...if its that bad give them a call they may be able to call something in for you. You can also try the extra strength tums that's what I have to do with this baby ....good luck I hope you find some relief