My daughter used to do this when she woke up from her nap from about age 2- when she dropped her nap at about 3.5. Nothing I would offer her or try to do would settle her down. She could not seem to get going after her nap. I let her watch tv for a little while and all of a sudden she would snap out of it and be her usual self. I think she just needed to wake up more.
The worst was when we had to get her up and head out the door right after nap. Asking for trouble .
She never had night terrors but was not a great night sleeper until she was almost 3 and had all her teeth. We also had never sleep trained her.