Hi Renee.

DS's sleeping pattern is VERY similar to Marnie's.
He is about 2 weeks olders i think (born Nov 29th).
He is also breastfed.
He sleeps through the night mostly, wakes up early and doesn't does a 1.5 hour sleep around 11am and then does a 40 min sleep later in the afternoon. on the odd occassion he will slip in an extra nap late afternoon, but only if he has a restless night (i think he is teething).
He seems happy, i'm happy...
DD was different. She would wake up early and have a 2 hour sleep at 11am and then a 3 hour sleep later in the afternoon.
They are not preprogrammed. Each child is different. I would only be worried if your baby seems OVERLY sleepy, or particularly distressed.