Baby drop in milk intake

Hi mummies.. my baby is turning 6 months soon and I have not started feeding solids. But suddenly from 1000ml a day her intake dropped till about 500-600 a day. She can go for more than 5 hours without milk. At night she refuses to dream feed and have gone on without milk for 14 hours. Thought to go to the PD but not sure what the doctor can do too. Any advice what it may be? She is teething but cannot be no need to drink milk?? #FTM