no sleep

My baby hasn't taken her usual long nap all day. She has fallen asleep for 20 minutes at the most today and would wake up. I tried to pacify her while she was laying in her crib but would eventually need to pick her up. She isn't fussy really, but she looks as exhausted as I do. She will be 9 weeks on Friday. I haven't had any caffeine today. I don't know what gives? Any ideas? Growth spurt maybe?