My baby already dropped but heartburn is awful

Abigayle • Abigayle. Mommy to Xavier & Xander. 3-17-16 3-11-17
My baby has dropped tremendously but my heartburn is so bad I can't even sleep at night. Tums do not work & I was told to take nexium which doesn't help at all either. I'm 38 weeks 3 days.. Is this possibly a sign labor is near or what? I can't seem to get it to go away :(