All right!! Help me out ladies!! Baby sleeping at night??

How many times a night does your baby wake up? Mine is 4 months next month. I put him to bed every night at 9:30 & he wakes up between 12:30 & 3:30 to eat. Then he falls back asleep for about an hour and some nights he just can't go back to sleep the rest of the night. He wakes me up once every hour. Many people keep telling me this is not normal? I feel like I'm doing something wrong. And I'm also so tired from no sleep :( . I would love any help. So, how many times a night is your baby still waking up at almost 4months old? Thanks ladies