Sleeping

So my baby was sleeping for like 8 hours a night then would wake up and feed then back to sleep for another 2 or even 3 somtimes. Then he got his 4 month shots and got a tummy bug and started waking to eat about every 5 hours. I'm not to worried he's been through a lot just wondered if anyone else did this? How long did it last for? Did they go back to their normal habits? Is he going through another growth spurt as well as everything else he's been fussy the last two days.