Suggestions for EARLY pain and D? Told it's IBS. How do I start? What do I do?

I have been suffering for 5 months. I wake up in the night (about 4am) from HORRIBLE stomach pains/cramps/spasms, so bad I cannot move. Then for the next hour I really feel like I have to go the bathroom (horrible pressure), but nothing happens. Then I get about an hour of D. Then I get the kids up and go to work!

I tried adjusting my diet and everything else the past 5 months. After losing about 35 pounds (in 5 months), exhausted, and in pain, I went to the hospital last week. I was there for a full week and they did blood tests, ultrasound, CT and colonoscopy. All negative. So they tell me it's IBS.  FRUSTRATING!

I have been reading a lot on this board - however I have still have some questions that hopefully some people will be kind enough to answer.

During the day I am OK - I don't have to run to the bathroom all the time, I just have lower pressure and lower back pain, and a burning in my stomach all day. This is bad of course, but the worst is the horrific pains in the night/early morning, along with the D.

Now I am just so confused as to how to start or what to do. I don't live in America, so the medications I mention are under different names, but my doctor gave me a few things, and said to try to see what works. The thing is, most of this stuff seems to be taken before eating or during the day - I need something to relax my belly during the night so I don't wake up in this unbearable pain.

Does anyone have suggestions of anything I can do to give me some relief? I am terrified to go to sleep, beause I know what my wake-up call will be!

I also haven't really been eating the past 3 weeks it's been so bad - just staying on Modulin (liquid food for IBD). I am meeting with a nutritionist this evening who deals with IBS/IBD diets.

Anyways, I was given:

1) "Spasmalgin" that contains Papaverine/Codine/Atropine Sulfate

2) "Colofac" that contains Mebeverine

3) My dr said if this doesn't work, to try "Nirvaxal"

3) "Colpermin" (www .Colpermin .com)

I also have Immodium, psyllium fiber, mint and Chamomile tea. But not sure how to use any of this stuff.

I was also told an antidepressent, such as Elavil might help (this is a Tricyclic antidepressants as opposed to an SSRI that I understand causes C).  Any opinions?

I know there is no magic answer, or this board would not exist - but any suggestions?

Many many many thanks!