Baby Sleep

My 5.5m old baby is taking catnaps and at night she cries before going to sleep. Naps for less than 45mins. Cries for max an hour to sleep for naps and at night but sleeps 10 to 12hrs at night with 2 to 3 wake ups yo breastfeed. Any idea why she does that? I see to it that there's so much activity during wake periods but she still refuses to sleep. She is rocked to sleep.