Not a lot of advice more than what you're already doing, but wanted to give you a
I've always had the same kind of probs, though now mine are intensified by ulcers, so I really sympathise. What's been working for me is to make sure I don't eat too much and make sure I don't go too long without eating, that helps the M/S too. Try raising the head of your bed, gravity does work for the heartburn. Take a gas reducer before you anticipate the pain, it's harder to make it go away than it is to not let it build up.
One other thing to try is to press on a few pressure points for digestion. My chiro showed them to me and they have been magic for gas. There are 2 just on the sides of the navel; start at the very edge and gently work out until you feel a tenderness and a spot that your fingers just fall into (mine are about 1" out, but it probably varies a bit in everyone). Then work the spot as much as you can handle it. There are also several down the tops of your thighs. I do these lying in bed with my knees bent, start at the knees right in the center and work down noticing the tender spots that your fingers fall into and work each one as much as you can (I have 4 noticible spots spaced about 4 - 5" apart). Anyway, it's a little woo-woo, but they help so much with gas bloating, and even with my ulcer pain. If you aren't used to working pressure points, you might need someone to try and find them for you first, but once you find them, they're a cinch to find again.
Best of luck. Just remember the first trimester is over before you know it