I don't know how to play a pair with a draw

[Coz]

I would have probably re-rasised the flop here too, my guess is that you are up against something like AT or A8, with the A of spades. If he flopped a set I think he would have liked to have gotten it all in on the flop. So I think that is around 15-20%, AT I think is about 40%, Ax is around 10% a complete bluff is around 10% and trips is around 20%. If I were you I would have taken the free card on the turn to draw to the flush. Yeah your bet does scream weakness, but I think he would have had to hit the flop to have made a bet like that. I would have folded too, plus you don't even know if you are drawing to the nut flush, he could have something like ATs.