4 month sleep regression

My bub used to sleep 12 hours a night, best sleeper. Since hitting 4 months she would wake up 3x a night. Have 2 good night's here and then. She's now 5 months and is waking every 3 hours. I'm a zombie.

I nurse her back to sleep. Sometimes she goes to sleep, sometimes it takes a bit to get her to sleep.

Any advice? I'm so tired