3 months old down to very few feedings a day - should I be concerned?

traveltheworld

DS has never been a "snacker", but for the past several days he is eating more and more infrequently, but on the times that he does eat, he eats for a long time.  For example, between last night and tonight, this was his feeding schedule (I try to offer the breast every 3 hours):

9 p.m. - ate for a minute; 

2 a.m. - ate for a solid 20 minutes;

9 a.m. - ate for a minute at most;

12:30 p.m. - ate for 20 minutes;

3:30 p.m. - ate for a minute;

6:15 p.m. - ate for 17 minutes.

So really, if you exclude those ones where he only ate for a minute (or less), then he had 3 real "feedings" in 24 hours.  He has the appropriate number of dirty and wet diapers.

Anyone else have a little one like this?