I agree that he either has the A and is playing you..... or the best he can have is the T. He may have even had the 4d5d and was hoping for a miracle. A min raise at the end would have been best IMO. If he puts you all in, well you were ready to go all in anyway, and if he has a low diamond, or maybe even a set if he doesn't believe you, he may still call. But the bet small, bet small, ALL IN screams I have an A or K please call me.