i had that problem the entire 6 months i was on Miralax. I hated Miralax and I think it also gave me bad gas. From my experience, I would stop the Miralax and stick to the Natural Calm and Acacia... but I'm not sure because I'm still trying everything out myself. I really think that the Miralax caused incomplete evacuation and pencil thin stools multiple times per day-- sooo very frustrating.
I've started taking Calcium/Magnesium as well, with Natural Calm at night and Acacia in the am... does that sound okay ? ? I've been able to have BMs, but usually a bit hard.