Major heartburn! 5 weeks

Hi! First off my situation is a little different since I have lupus and mixed connective tissue disorder. The levels are stable, Praise God! Apart from normal pregnancy symptoms like tender breasts, and slight cramping every now and then, I've had a couple nights of BAD heartburn! Like the kind that feels like major pressure making it almost impossible to lay down. I took Pepcid which helped a lot but it happened again last night and the Pepcid wasn't as effective. Is anyone else having issues with this? If so what has helped? I know not eating before bedtime is crucial...