DadDude is right
- we've always been advocates of fun and joyous learning, but if your child isn't in the mood for your lessons, then perhaps it's best to lay off them for a while. Give your daughter a day or two of rest, even for as long as she needs to replenish her enthusiasm for the lessons.
Perhaps it's also time to provide her with different learning experiences - give your daughter a variety of ways to learn by spending more time with toys for tactile stimulation and motor skills development. After a while, she may learn that she has missed her flashcards, and will be happier once you resume her lessons with them.