He might be confused. He might not know how he got here or why he couldn't save Tyki. And he still doesn't know what stopped him from finding Tyki in the first place. But even though this mental haze, it doesn't change the fact that Jonathan Strange is obnoxiously arrogant.

As such, Tyki calling him weak lights a fire under his ass more than anything else. Strange's expression rapidly shifts from hurt to downright annoyed. Weak?! How dare he! He brought magic back to England, he saved his wife, he's dispelled a few enchantments (though he can't remember which ones right now), he is anything but weak!

"I am one of the greatest magicians of the age," Strange continues, more to himself than to Tyki. Though with the next sentence, he tries to push back past that confusion and that distress to just give Tyki a glare. "Whatever stopped me wasn't my own failings."