Is it normal for a baby to have a change in sleep pattern?

Hi doctor,

My daughter is 15 months old, and it has been three weeks that she did not sleep at night. 1 to 2 hours at most and then she will cry waiting for me to bring her to the living room because she wants to play. She would not stop crying if I ignore her (I am trying to let her try to soothe herself), even if I try rocking her or put the pacifier. She will only stop crying once I brought her to the living room. I am working, so I sent her to a babysitter during the daytime. I thought she will sleep more during the daytime, but apparently, her sleep routine is just the same as before. Her babysitter said that she slept for 1 to 2 hours in the morning and the afternoon.

She is healthy, so active, happy as usual and looks completely fine to me even though she does not sleep enough. Is this normal? Will this new habits affect my daughter's health or growth? What cause her sleep routine to suddenly change? (Previously she will sleep throughout the night, with 2 to 3 times milk feeding in between). What can I do to put her back to her previous sleeping habit? I really need advice.