Welcome to HealingWell!
Are you still having fevers? I know you mentioned you've had the slew of tests done, but have you had the camera pill? Fevers aren't common with IBS and it makes me wonder if indeed you do have IBD. Everything else, however, does seem to be signs of IBS. Unfortunately, those types of symptoms are common for many digestive ailments.
The pain and uncomfortableness you describe could be caused by gas. Do you take anything besides a probiotic and antispasmodic? You might want to throw in some anti-gas med or even start eating yogurt, like Dannon Activia. Activia has helped many of us keep regular and get the gas down to a minimal.
Also, if you are being kept up at night, you might want to considering having dinner early in the evening. Eating just a few hours before bed can cause problems for those of us with gut troubles.
Hope you have a great New Years!!!