4 Month Old Sleep Pattern

Hi! My baby is 4 months coming 5 months in 2 weeks. I've read so many articles and posts from mummies saying that by 4 months, their babies will sleep long hours and even through the night! However, my baby still wakes up at night. She will sleep usually around 6.30-7.30pm. Wakes up at a 3 hour interval. She has difficulty in taking naps in the morning as well. Her naps are usually rather short, 30 min to an hour. She takes about 3 to 4 of those naps in the day. She is also quite a fussy baby. She either needs people to entertain her or carry her and sometimes she just cries. Help pls!