Bedtime

Hiya, just looking for some advice with my 7 month old little girl at bedtime!
She will go down lovely at 7pm and then usually about 30 minutes later she wakes and cries and gets herself into such a state that she will be sick, bringing all her milk up! This has happened 4 times in the last week! 
She will then not end up going to bed until 8.30/9ish after all the commotion...
She is definitely tired enough as she is rubbing her eyes etc before I put her down and she only does this at night... any other nap in the day she will just fall asleep!
And she has only just started doing this, used to just go to bed.
Any advice would be welcome,thanks in advance! Xx