Girls, can anyone tell me if they've experienced something like this? …

Girls, can anyone tell me if they've experienced something like this? The baby is under 6.5 months old and used to sleep alone in her crib. Suddenly she started sleeping with us. Before, we fed her on demand, then she would fall asleep after feeding. Now she eats, falls asleep, I put her in her crib, she starts crying, I lay her down next to me and she sleeps soundly. It's been half a month now that I can't put her in her crib.