Baby not sleeping in bassinet

My baby is 6 weeks (although he was born a preemie so technically he’d be a newborn since his due date was yesterday) and he has been having a hard time sleeping in his bassinet. I’m not sure if it’s because I started breastfeeding because he sleeps in the bed with me after I feed him or if it’s because he reached his due date or what but it makes it hard getting things done because he’ll cry after like 5 minutes then i’ll pick him up and he’ll sleep then put him down and again the same thing. What can be causing this? What can I do? Also sometimes he only breastfeeds 5 minutes too, is that cluster feeding?