I'm sorry to hear of the setback. I'm wondering if you are using any natural stool softeners as well. I take two emergen-C packets every day (the vitamin c helps soften stools), a magnesium citrate powder (muscle relaxant), as well as a wheatgrass powder in the morning and a 400mg magnesium oxide tablet and triphala (by Himalaya) in the evening. I also eat an oat dish in the morning and beans and rice every evening.
Wishing you luck. Like you, I want to get off the miralax (and the nitro cream). If I do end up getting LIS, that would be my primary reason for getting it.