Your post-flop bet was too small. With a $.67 pot, I'd bet $.45. The $.20 bet looks weak, and is something I would probably challenge if I was in the villain's shoes if I had any high spade or even a gut-shot straight draw. Or if I'd seen any sort of post-flop weakness from you recently.
You stabbed at it, the information you got from your bet said "Hhe has you beat," so I think you did the right thing by folding.
But again, I'm left wondering if his re-raise was a reaction to your weak continuation bet, or if he really had a hand?