sleep problems

Am
Is anyone else have a 5 month old getting up like every two hours at night? He feeds all those times too.  He was a month early when I delivered so I'm wondering if he is going through the 4 month regression cause technically had I went full term he would only be 4 months old now.
Any suggestions what it is and how to maybe stop it he used to sleep through the night but the last 3 weeks to a month.
Thanks :)