Are you eating proper milk? Cos that's a trigger...even with the lactaid! Lactaid only works to break down lactose...whey and casein (other components of milk) are also IBS triggers.
Are you still using a SFS? They are very helpful in combination with diet, etc. And stress-relief techniques like yoga, hot baths, meditation can also help with the stress of IBS...even tho it's the IBS that causes the stress, it can still make the IBS worse.