My daughter is 16 months old and has slept through since around 3 months. Within the last 3 hours,…

My daughter is 16 months old and has slept through since around 3 months. Within the last 3 hours, she has woken 3 times but she is hysterical. This isn’t like her and I know it’s not her teeth or anything else as I know how she cries and moans in the night if she’s in pain. Any ideas on what this could be. She’s gone back to sleep but no doubt she will be awake again soon.