colonic inertia and lazy stomach

I am under a GI's care.  I have been diagnosed with colonic inertia after a sitz marker study, defogram and years of severe constipation.  The moved up and did upper scan and discovered the slow digestion problem.  I am on domperidone for 3 weeks and had a galllbladder ultrasound (fine).  I am having a hidascan this week.  Feel like doctor does not really know which direction to go in after this.  He feels the colon and stomach are separate issues but I am wondering if I have some type of muscle disorder since nothing is working.  I only get constipation relief by doing warm water enemas every other day.  Amitiza, zelnorm, mirilax, cristolase, etc. never worked.  They even combined amitiza and mirilax and the bloating was so unbelieveable that people thought I was pregnant.  Is this neurological?  Just looking for some new eyes to look at the situation.  I also had blood workup for thyroid and that was negative.  Think that is all they did though.