BIG hugs Pixie it is such a hard thing to go thru.

I work in childcare and i second was beatrix said, the longer u stay the harder it will be for her, try and make it as quick as possible, sign her in put her bag away give the staff any info u need and say goodbye giving her a big kiss and a cuddle saying you'll be back after work. I know this sounds really hard to do, but it will better for your DD in the long term. Always say goodbye and tell her your are going, I've seen some parents sneak off when their child is playing and when the child realises mum or dad has gone their reaction is usually a lot worse than if mum or dad had said goodbye.

When i drop my DS off at FDC i try and do exactly the same thing and most mornings we have no tears occasionally we do and it is heartbreaking to leave hearing them so upset.

Also crying when u return to pick up is completely normal lots of children do that, it like they are so relieved and happy to see you that their first response is to cry, my DS went through that initially but it didn't last long. Once she gets in a routine and realises that daycare is a regular thing I'm sure she will be fine.

make sure you ring and check on her as often as u want, as a parent that is your right, and don't ever feel like you are burdening the staff it's their job to reassure you and let you know how your DD is going. thats a common thing i hear among parents, they say they feel silly ringing but u ring as often as u want.
HTH and good luck hun, i hope it gets better quickly for you. xxxx