You jacks block his straight. So he's definitely representing the flush. If you add up all the preflop bets it comes out to 94 assuming your recollection is accurate. So your 50$ bet on the flop gives him great odds
to draw (with the reverse implied considered) maybe a bet closer to 70-100 would have been better here?
Its really hard to tell what he has though. Definitely a gross spot. I feel like we can rule out drawing to an overpair though since he called your flop bet, which he wouldn't do without a good draw or a made hand. he could have pocket pairs since he called your 3bet, but we can't really rule out the flush since your cbet seemed a little on the weak side.
I think I would have to say, bet 100 on the flop and if he calls check/fold the turn