More two pair problems!

Ok cash table, 6 players.

I call from the sb with 8 6 off (my first call for a while as ihad nothing but crap like this)

Flop is 8 6 4 with two diamonds.
With this being a dangerous flop i hit it hard, 1 and half times the pot. All but one fold. Chaser i think.

Turn is another damn diamond, a 5 so i check to him and expect a raise which doesnt come. This seems odd as when people have hit the turn or the flop at this table they have bet it and people have just folded.

River is another 5 (clubs i think)

I still think hes got a flush but hes just decided to slow play it, but i put out a minimum bet to check and he just calls. Turns out hes got pocket qs and beats my two pair 6s and 8s with q's and the 5s on the table.

Did i play this right? I tried to get the drawers away but thought this guy obviously wanted to chase. When i thought he hit it i just checked as to not waste any more money.
Yet it turns out i misjudged, was i right or wrong with my play? I didnt want to hit the river hard as i thought id be wasting my money.

Although I have a feeling he still would have called your bets (sounds like low stakes) I think you should have bet again on the turn.

While you may supsect he got the flush (I don't know why) you should still bet because I'm pretty sure you weren't 100% he was chasing the flush and you want him to pay for chasing a flush draw he may have caught on the turn.

also, min. bets in NL are pointless.

Your bet on the flop was nice. The 5 on the turn is a problematic card since it completed both the str8 and flush draws. would bet the turn to see where I stand, it makes more sense then checking the turn and betting the river.

Your opponent played the pocket Q in a very odd way which does not make any sense to me, there is no way I would put him on a higher pocket pair.

bet the turn, then check/call small or fold the river. never minbet.