Until you can get into the GP, it helps to prop yourself up when you sleep either by: propping up with several pillows, using a foam wedge, or raising the head of your bed on blocks. This link has some acid reflux diet and heartburn recommendations which might help too in the meantime:

http://www.gicare.com/diets/gerd.aspx

http://heartburn.about.com/od/goodfo...eflux_Diet.htm

Sometimes meds can be the culprit or may just develop it unrelated, hard to tell. But if your psych meds are working for you, it's not worth stopping to find out, there are diet and acid-reducing meds to accommodate for it, talk to the doc.