My acid reflux started at week 16, almost as soon as the morning sickness had eased. I managed through to about week 20 wth chewable antacids such as Tums, Rennie and Mylanta, then graduated to the liquid Mylanta (which caused violent diarrhea) then Gaviscon. But the acid just kept getting progressivly worse. By week 26 it was unbearable to the point that I could not even keep water down and would end up retching. The doctor prescribed Zanac, which I used in conjunction with the Gaviscon, this was a lifesaver until week 30 when the horrors started again. Even when sitting or standing, after any type of food or liquid it happens. I slee sitting-up on the couch and have juststarted acupuncture and a chinese herbal medicine to try and reduce the effects (never been a believer, just started and haven't had much of a change as yet).
I'm 31 weeks now, 9 weeks of this hell to go - people tell me it's all worth it in the end, I'm sure that's true bu I'll reserve judgement!!!!!! 
Hello!
First, congratulations to you! Reflux and pregnancy go hand in hand so you have lots of company. It sounds like you and the doctor are trying a variety of acid reducer medications to control the reflux. That is a good start.
How and what you eat can also make a difference:
Wear loose clothing around your waist.
Avoid bending at the waist after a meal. Let someone else pick up something from the floor or tie your shoes.
Avoid eating before naps or bed.
Avoid acidic food such as tomatoes, oranges, spicy foods and caffiene.
Eat small snacks rather than meals. Chew slowly and carefully.
Fried and high fat foods digest slowly so go easy on these foods too.
Some people have success eating first, digesting and then having a drink.
Keep your digestive tract moving by increasing fiber and avoiding constipation. I know this is challenging with all of the iron in prenatal vitamins.
If you are having serious issues keeping food and fluids down, you need to go to the ER or get a consultation with a GI doctor.
I think the biggest challenge with reflux and pregnancy is getting all of the nutrients and calories in without causing painful symptoms. As much as I craved chocolate cake and fun foods, it always came back to me in the form of painful heartburn.
The good news is, pregnancy related reflux often goes away after birth so make a list of your must have foods for after the pregnancy.
Good luck,
Jan Gambino
The Reflux Mom