Dare I say the "C" word?

I've had a rough past few days.... I feel really badly for my 2 year old who is getting the short end of the stick because my frustration level has peaked and she happens to be around the most. I have come to the "unofficially diagnosed" conclusion that my 3 month old daughter has infant colic. (From Wikipedia- "[an infant has colic if] she cries intensely more than three days a week, for more than three hours, for more than three weeks in a month." This and many other things have led me to this conclusion. I will briefly allow you into my world for the past three months.
I tried to breastfeed- it was a DISASTER!!!!!!!!! My baby did not sleep a wink, in fact she would only sleep when she was on the breast. I only found out she was not getting enough nutrients and was "pretend sucking" (really only sleeping) because she was borderline Jaundice and I had to supplement. When I tried to take her off the formula and only offer breast milk she became worse so I had to keep up with the supplement. With this began the bouts with the formula. Essentially, the only way she would calm was if she was held- not in a carrier or sling, in MY arms in a certain position that does not leave any hand free.
Now mind you, this may not have been SO HORRIBLE had I not had a two-year old running around craving my attention. She is very well-spoken for her age and told me very often that every time she wanted to do something with me it was "BABY BABY BABY EVERY TIME!" I realized at this point that if I did not let up on trying to breastfeed, the relationship between my older daughter and her baby sister was going to be a bad one.
The first few days (I can't even pretend to remember accurately because it really feels to me like one big blur-not in a good way) were okay. She fed and slept appropriately, but then the screaming began. No, not crying, SCREAMING!! She would have days with one hr TOTAL of sleep and this did not mean that she was up just hanging around, nope, she was screaming without being able to calm. I would get a slight glimpse into what I knew could be a reality (as per first child) but it was only a glimpse and it was followed by endless screaming and fussiness.
This, my friends, has not ended. I have tried changing formula several times from sensitive to gentle to hypersensitive to I don't even know what else. I have tried "natural" home remedies like Chamomile and gripe water, but all things only offer temporary relief. I'm at my wits end and don't know what to do.
I am sure there are parents out there who have battled with infant colic (because I'm with you- this is a battle, one I am trying desperately to win, but a battle nonetheless). PLEASE PLEASE PLEASE let me know I am not alone.... and if so, what have you done???? Does this end? Maybe just hearing from someone who has been through this can help me see the light.