1 month old hit head on carpet too hard?

i was changing my daughter , she is one month and almost a half, and i kind of plopped her down on the floor , her head it the floor and she cryed but not for long she was hugary, but now i am scared because she has been a bit more cranky then usual, (but she also got her hepatitis b shot 2 days ago) and i dont know if its just getting t my head to much or if i think she is sleeping more then usual. i dont know, it just seems like she wakes up to eat then wants to sleep, but i can remember last week in the mornings her staying up a little longer then she is now and watching tv with me or playing or reading a book to her. now if she doesnt sleep she tends to get cranky. i dont know if im paranoid , because her head didnt hit hard but i just was half asleep and plopped her down being less carefull then usual. any signs i should look for?