What. Is. Happening?

I know it's common for kids to ramp up the bedtime antics as they get older, but our 2.5 year old setting a whole new standard for herself. She has been a great sleeper since we did sleep training at 8 months old; minimal wake ups, happily went to bed without a peep, etc. But for the past six weeks she's been slowly trying to stall bedtime. Usually we were able to nip it in the bud quickly and get her down, but for the past 5-6 days she's also started screaming and yelling at the TOP of her lungs as soon as we go to place her in her crib. She wants us to hold her as she falls asleep or sit in her chair while she sleeps in her crib. We've indulged this a few times for our sanity, but I know it can't go on like that.

I assume it's some sort of separation anxiety, and I want to be sensitive to her while also making sure she knows she can't play us to get her way. I've tried incentivizing bedtime with a sticker chart (that wasn't appealing to her) and I've told her that she doesn't have to sleep, but needs to read quietly in her crib (also didn't work).

Is this one of those situations that you just had to ride out or did you find a trick that helped ease the bedtime crazies?