It would seem that Charlotte is on a nap strike. Ever since we returned from our holiday, Charlotte has fought naps. The thing is, she could still use a nap, at least most days. She will be obviously tired and cranky, but most of the time if I then try to get her to nap, she will fight sleep and stay awake.
Right now, I just go with it and don't push it too much. If she actually manages to stay awake all day, bedtime is actually easier and she's more likely to sleep in her bed. She's also more likely to stay there for a longer amount of time before she crawls in with us. However, what often happens is that she will crash late in the afternoon, throwing off bedtime completely. Oh well, it's just a phase. I will be glad when she either settles into giving up the nap completely or goes back to an earlier nap.