Why is my baby waking up multiple times in the night?

My 7.5 month old sleeps at 7.30-8pm and has no trouble sleeping till 10.30. After that, he wakes up 3 to 8 times till his morning awake time at 5am. This increase in night time wakings happened in the last week before which he would wake up 3 to 5 times in the night. He naps during the day, 3 naps totalling 3.5 hours. How do I get him to go back to sleep on his own? He sleeps with me but I don’t pick him up or rock him in the night, instead he takes a feed or two or comfort feeds from the bottle. Any advice would be great I am desperate to solve this since the sleep deprivation is killing me at work!