Separation anxiety - when does it get easier?

So it took Zach about 2 weeks before he became comfortable to go to preschool. It didn't matter that he had 4 friends already there from daycare - Hailin, Helena, Ryan, and Zuri. He would still lie on the floor and scream "Mommy!" when I left. Now, he says, "I like to go to preschool now, Mommy." Such a good boy. I wonder what he eats though. Sometimes, he'll come home and his lunch is still in his lunchbox (Cookie monster plastic bag). I decided to be a little adventurous one day and packed him a small yogurt in his lunch, included with an ice pack. The yogurt returned. He said he likes yogurt but didn't want to eat it at that time. I usually pack him 1/2 PBJ sandwich, some crackers or cookies for snack, juicebox for snack, and pretzels or something. The boy doesn't eat much at home either.
Asia still cries when we drop her off at daycare or even when the babysitter comes here. It's sorta sad. When she sees her cousin Justin now, she cries. Even if we're not at home, she'll cry when she sees him. He probably regrets saying he'd babysit her now that he gets that reaction. But with all her babysitters, she only cries now for maybe 5 minutes and then stops. I just wonder when that will end. I hate having her cry and the babysitters don't like it either even though they're used to it now. It's not like I don't spend lots of time with my kids. And it's not like they're sheltered. Yet they still cried when separated from me.