Sorry to hear your having to go thru this. While my little guy never really cried, he did have tummy troubles. It also started around 3 weeks. Instead of crying he was real irritable. Gripe water was a godsend for us. But even through the Gripe Water made him a new baby, I knew he'd still have the problems if I didn't give it to him and wanted to know what was wrong with him. He was diagnosed with Reflux, and put on Enfamil AR (Added Rice) and put on Zantac. After about three days we had the perfect baby. Once in awhile he would get a tummy ache, and the gripe water would solve that. We weaned him from the Zantac about a month and a half ago, and are currently getting him off the Enfamil AR. We haven't used the gripe water in over a month, And he's still a VERY happy healthy baby!
Does your daughter spit up a lot? Also, as 2fast4u said the swaddle blanket could be a good purchase. Swaddling her tightly and putting her in a swing may help soothe her.
I thought we'd never find "The Magic Touch" to make my little guy happy, but we did, and you will too.