Just know that you can't always stop her crying. But your physical closeness is the best thing you can give her: as much as she needs. She'll tell you with her cries that she needs you. Babies are HONEST. Don't ever let her cry it out, unless you are absolutely going to lose it and she might feel your frustration or you might hurt her, physically and/or emotionally. Otherwise, just relax. It's o.k.; babies cry - and they eventually stop and sleep really well afterward. :-) You're not failing her if she has long crying episodes. She'll come through this - and so will you. Here's a way I would let off some steam while I was rocking or walking with her (with no one else around, of course): Sing a song to your favorite lullaby tune: "I'm sooo frustrated, I'm going nuts, I'm going to pull my hair out, the paddy wagon's gonna come and they're going to have to give me a big shot and put me in a padded cell..." :-) I find that amusing myself saves me from getting too upset or frustrated. Sometimes you just have to get that release.
Hang in there and take care,
J. Smithson
Loving Hands Learn 'n' Play
http://www.lhlearnandplay.com
edit: I agree with Sherree, and wanted to clarify: I don't mean to say you must HOLD her 24/7: no no, not possible. I love the sling idea too! But even if you must, God forbid, say: eat, drink, take a bathroom break, get a chore done, your physical closeness, i.e.: being in the same room and paying attention to her is very important. I think, even putting her in a swing for a short time (5-10 minutes) is acceptable: whatever seems soothing and includes you being near her. "Cry it out," to me, means leaving her to feel all alone and forced to soothe herself. Based on research and experience, I don't agree with that method AT ALL.