is your baby well? does he have a cold at the moment or a temprature?
those are the first signs to look out for if hes been vomiting or having runny stools
that smell like dihoreah if yes then take him to the doctor
another thing is he may need a nap in the afternoon or perhaps an earlier bedtime
many people put their babies to bed at say 8 pm when really they need to go to sleep from around 6pm
babies need around 12-14 hours sleep a day this is up until they reach about 5 years old then they need around 10 hours
when they get to 8 years old around 8 -10 hours sleep
11 onwards around 6-8 hours
babys are sleepy little things it hard work growing a body and teeth and learning to walk..
if your baby isnt unwell then hes probably due a growth spert...
hope that helps if in any doubt ask your health visitor