My 17 month old sleeps amazing at night & for her first nap, but refuses to go to sleep for her 2nd nap, even though it is VERY clear that she is exhausted. We lay her down awake for the 1st nap & bedtime, & she falls asleep with not even a whimper. She physically keeps herself away for the 2nd nap, doing things like smacking her face, kicking legs, flailing arms or babbling. HELP! I have an extremely exhausted baby in the evenings, & I have ran out of options.
I know it's painful to see an obviously tired child refuse to sleep. But we can't "force" our children to eat, sleep, or poop -- they are in control of those basic bodily functions. And children rapidly change in their sleep cycles and need for sleep, so it's not uncommon to experience what you describe. It may be that she's ready to try to drop that second nap of the day. Experiment with it for awhile, putting her to bed at night earlier than usual to make up for the lost sleep -- and expect more afternoon crabbiness until she adjusts. It may take a week or more. Just be glad that she sleeps so well for you at nighttime and her first nap -- lots of other parents out there envy your good luck!