Colic or just plain Cranky?

Okay, so there are many joys in motherhood, but this is definately not one of them. The twins will go through these crying spells for 2-5 hours at a time and when they get going, there is no stopping them. So, after I had fed both babies, changed both of their diapers & clothes, and then rocked them in the rocking chair, they were still going, I was getting frustrated, not at them, but at me for not knowing what to do to please them. I just had to take a moment for comic relief and snap a picture, that way I have evidence for future reference. Notice the shirt: "I don't have to be good, I'm cute..." I thought these onsies were adorable when we got them from Darin's aunt Bonnie, but if they are going to act like this when they wear them, these onsies might have to go in their baby keepsake box. I don't really think it was the shirt though because they do this on days that they are not wearing that onsie. Have any of you ever had an exceptionally fussy baby? What are the symptoms of Colic? Any advice? HELP!!!