Extra Sleepy Baby?

My son has been extra sleepy for the last few days. He got his 2 month shots last Thursday and I feel like he has been sleeping so much more since then. At night he still wakes up every two hours or so and during the day will only wake up for feedings it seems. No fever or anything other than a stuffy nose to indicate illness. Still a happy smiley baby when he does stay awake. Anyone else have an extra sleepy baby between 8-9 weeks?