3 week old fighting sleep?!

lauren

my baby is 3 weeks old today, for a little over a week he's been fighting his sleep AWFUL, he'll stay awake up to 3 hours, he's breast fed, and refuses a paci, he'll just sit there awake and every now & then he'll cry, around the 3 hour mark he'll get really fussy until i put him on me, and he'll just use me as a paci. and suggestions on what will help or why he's doing this?