5 Minute Feeds??

Crystal • We've got this 🐧

My 4 month old (just made four months today) used to feed 10-15 on one or each boob (it always varied). The last three days is now eating for 5 - 8 minutes, releases the boob and refuses to take any more. His 4am feeding, after sleeping 6 1/2 hrs he did eat 15 minutes on a full boob but since then will only eat for about 5 minutes. Should I be concerned? Or has he just become a boob master??