I am having the same issues - my daughter is heading to daycare (with a woman in her home and w/ my mother-in-law) in a week, and it is hard. I thought that this being my second time around it wouldn't be that hard, but it is.
Be sure that you give the provider all the information they need about her. What she likes to comfort her, what she doesn't, when she eats, sleeps, etc. That will make you feel better that at least they'll know that tickling her left foot calms her down when she's cranky - or whatever it is that works for you.
Be sure to call and check in - it will calm your nerves that she isn't screaming in the background and it makes them know that you're really engaged.
And just remember - you know where she is, you can go get her if you need to. But she will never think of someone else as Mommy! I was so worried about that - because my first daughter was in an in home day care and with my mother in law as well so the relationship were close, but she still knows who her Mommy is!
Kids in daycare do great - they get socialized, etc. So try to relax just a little bit. You'll get through it - one day at a time!