Wow, this is an interesting one for sure. I think that maybe the real clue here was pre-flop. His call of your raise pre-flop suggests he might have had a hand, something in the AT or better range, or he was solidly fishing with a pair of suited connectors or something like that.
you a whole lot more. Difference here is that pre-flop he just called you, after the flop he is raising you. If he thinks you are bluffing
, he still has to think he has more than your bluff. It's about even at this point with the idea that he hit well, like he has a J, or his suited connectors are 54. He could have gotten very lucky and have J4 or J5 suited, which means he is on two pair.
The turn tells you a lot more. Your check is blank, he bets a pretty solid amount, suggesting at that point that he has a reasonable made hand, that the brick 2 means nothing to him. Your call here is probably a very small bit loose, but not unreasonable.
The river makes it worse. The only way you get out here is that he has one or two pair, or Jx rather than xJ. Worst scenerio is J4/J5, because as your hand improved to trips, his hand turned into a house. The only clue here maybe is that he felt his hand was made before the final J.
I would say that, my guess is either he played 54 suited and hit good, thinks his 2 pair is great, or he had two high diamonds (even AK) and was chasing the flush to the end, and left screwed, he is trying to push you out.
If you make it to the end, sadly you almost have to call. I agree with ScottishMatt here, it probably would have been better to fold to his 5.75 bet, but once you have made that call, the $15.50 on the all in is ALMOST a good call, your $15 will get you back about $35 or 2.3 times your bet. I think you shouldn't have put yourself in the place to make that choice, you could have stopped earlier.