Welcome to the joys of cluster feeding. this is from
www.kellymom.com, a great website for breastfeeding info:
Cluster feeding, also called bunch feeding, is when babies space feeding closer together at certain times of the day and go longer between feedings at other times. This is very common, and often occurs in the evenings. It's often -but not always- followed by a longer sleep period than usual: baby may be "tanking up" before a long sleep. For example, your baby may nurse every hour (or even constantly) between 6 and 10 PM, then have a longish stretch of sleep at night - baby may even sleep all night.
Cluster feeding often coincides with your baby's fussy time. Baby will nurse a few minutes, pull off, fuss/cry, nurse a few minutes, pull off, fuss/cry... on and on... for hours. This can be VERY frustrating, and mom starts wondering if baby is getting enough milk, if something she is eating is bothering baby, if EVERYTHING she is doing is bothering baby... It can really ruin your confidence, particularly if there is someone else around asking the same questions (your mother, your husband, your mother-in-law).
This behavior is NORMAL! It has nothing to do with your breastmilk or your mothering. If baby is happy the rest of the day, and baby doesn't seem to be in pain (as with colic) during the fussy time - just keep trying to soothe your baby and don't beat yourself up about the cause. Let baby nurse as long and as often as he will. Recruit dad (or another helper) to bring you food/drink and fetch things (book/remote/phone/etc.) while you are nursing and holding baby.