Align (Bifidobacterium infantis) is a probiotic, which is suppose to return normal flora to your digestive system and in return reduce the amount of gas and relax the IBS symtoms.
As to the dark stools, if an occult blood test came back negative, it could be some of the medication or foods that are promoting black stool (i.e. spinich or other dark green vegetables, Maalox...).
I would, as I've said earlier, ask to be checked for diverticulosis and see if that isn't promoting the gas and pain issues. Fecal matter that remains in the pouches of divertulosis patients will create gas as well as inflamation if left unattended.
Just my thoughts...
Have you been checked for diverticulosis? Pain in the lower left quadrant of your abdomen "can" be diverticulosis.
IBS pain tends to move around the intestines as it spasms. The fact most people feel it intensely in the ilial/cecal area is because that's where the small intestine is connected to the large intestine.
The fact you say left side makes me ask you to talk to your doctor about the possibility of diverticulosis.
Be concerned enough to get it checked out, but being "overly" concerned is going to create a cause and affect issue that is IBS for sure. Because for many people, IBS is intensified by stress that produces more stomach acid.
Just a thought...