Deep breath, Christy. This too shall pass! If she won't sleep, can you do a super-early bedtime?
If it makes you feel any better, in December Ethan went NINE hours without a nap. He finally crashed at 4pm for about 40mins. And we still made it through the night. You will too!
The reason I asked about wind-down was that Ethan needs a fairly long period of quiet time before we start his 'wind-down' proper. We lie in bed together and read books and talk, and when he finally gives me a definite sleepy sign, we do our wind-down (cuddle and songs, zip into sleepsack, lights out). Not sure what your A is like just before bed but is that worth a go?