Hi H.!
My daughter is not as old as yours, she's only 13 months, so I'm not sure exactly how a 17 month old behaves, but here's my take on it.
I know with children, they will be more resistant to going to sleep if they are *overtired.* You might want to make her bedtime EARLIER. Sometimes even just 20 minutes helps. The key is to catch them at the "right" time before the meltdown occurs.
My sister loaned me a book called "Healthy Sleep Habits, Happy Child" by Marc Weissbluth. He goes into a lot of detail as to why children require the sleep they do and what TYPE of sleep is required. I know all children are different, but this has definately worked for us!
In my experience, if it's an ear infection, she won't stop crying when you pick her up.
Let us know what you figure out! Good luck!