Any advice?!!!! Please!

Tey
Has anyone heard of this? Anyone experiencing this? Experienced it? What do you know about it? How to manage? 
My baby is 4months and 18days and she was sleeping wondeful for a hole week! She slept from 11-6 am, 10-6am, sometimes even until 7-8am... at the week and one day she started waking up every 3-4 hours 😰 I'm exhausted!! And last night I read that this was a 4month sleep regression... I never heard of it before. Help please!!!!!