What Could Bulging Of Anterior Fontanelle In Children Suggest?

My 2 year old daughter appears to have a bulging anterior fontanella, should this have closed by now? she seems to be in good form no fever however last night and the previous night she vomited once each night, she is not complaining of being sore anywhere and is sleeping ok. Is it anything serious I have booked into my GP we have an appt tomorrow