LO is 9 months old, and she's never been an awesome sleeper. At 6 months we sleep-trained, so she puts herself to sleep for naps and at bedtime, and wakes up 2x a night.

For the past few days, she has been refusing to go/stay asleep. Waking up 3,4,5 times a night and yelling through her naps.

Is there a 9-month regression? Did anyone have a similar experience? We were just getting back on track after teeth, colds, pulling up, crawling, etc.