Help!, Worried, Can't figure out what's wrong =(

For the past month or a little longer now I've had chronic loose, mushy stools.  At first it was in the mornings when I woke up.  At about the same time everyday.  I would have some gas before  I had to go and that would be a little crampy.  I've had this crampy gas my whole life pretty much.  I recently had a colonoscopy that was very painful when they introduced the air.  It felt like that same kind of cramping.  The doctor said that I had a very tortuous colon.  I think this is probably why I have the cramping when I get gas moving through my system.  Passing gas always relieves it and I don't get this particular symptom often at all.  Usually, I had just this one loose, mushy bowel movement for the day and the rest of the day I would feel fine.  Maybe some days I would go back to the bathroom a couple times.

I went to the doctor and had urine testing, blood testing and stool testing for parasites and such.  All came back normal.  I also had an abdominal and pelvic ultrasound, also normal.  She referred me to the GI doctor recently where I had a colonoscopy to rule out Chron's and Colitis.  No biopsies were taken.  I had some Grade one internal hemmorhoids and the very tortuos colon was discovered, but nothing else was wrong.  The doctor thinks I have IBS.  He prescribed Bentyl and Lomotil.  I am not taking the Bentyl because I don't have cramping typically associated with IBS.  I waited a couple days after the colonoscopy to start taking the Lomotil.  A couple days after the procedure I woke up in the middle of the night with watery diarrhea. (i know waking up mid-sleep is also not typical of IBS).  I took a Lomotil the next day, but that night it happened again at almost exactly the same time.  I went to my regular doctor that morning and told her that I really don't think I have IBS and asked what else could cause this problem.  It's causing me alot of stress.  I'm barely able to function.  I've gone on IBS diets, added fiber, eliminated dairy products and red meat and had no change in the mushy stool.  I've been taking the Lomotil (1 every 12 hours) and it made me not go for almost 2 days.  I finally had a bowel movement and it is still mushy.  Not even mushy, but just like tons and tons of little pieces not even mushed together.  My GI has ordered a Celiac test, but I haven't been able to talk to him even to ask questions or tell him I really don't think I have IBS...or to tell him that the Lomotil did not help produce a solid stool.  My regular doctor mentioned malabsorption when I saw her the other day.  I'm getting worried that something is very very wrong with me and that I will just be written off as having IBS when I know that's not the case.  What else could cause my bowel movements to become mushy like this..even after food having been in my system for 2 days?  This is very strange because I have taken Immodium in the past and it constipates me for a couple days and usually produces a solid stool after the constipation wears off.  Of course after that solid stool the mushy stools would just come back every morning.  But this is really starting to scare me, my body is just not digesting food properly and it seems like it's gotten worse since the colonoscopy.  I've lost weight and I feel terrible.  The stress of this is really taking a toll on me as well. What should I tell the doctor I want to be tested for?

[MercyNeeded]

Seems you've had a lot of tests and all normal results.  Stress can really mess up your insides!  I found the following site that explains functional bowel problems.  Read through it and you might discover your condition and help yourself to be calmer:
http://www.acg.gi.org/patients/gihealth/functional.asp