Sounds like stress to me. Even if you think you've gotten rid of all the stressful stuff in your life you still have your subconscience. Sometimes you can't even tell it's a problem - you feel fine, doing all the "right" things, but you still are having strange problems.
Have you considered biofeedback or CBT?
Please keep us informed of your progress (or lack therof...hopefully the former).
Angela
ps..Hannasnana has it right on about the cramps..I'd bet the farm (if I had one

) that it's a potassium deficiency, or some other vitamin problem because of the loose bowels.