Just another draw

[Net Warrior]

3-6 on line averaging 40% seeing the flop and 6bb pots. 1st hand in BB I get As6s. UTG raise, MP coldcalls, CO calls, I call. I'm getting correct odds to call with one caller so this is a nice overlay, right?

Flop 4c 7s 8c

I check my 4 outer + backdoor flush. Anyone semi-bluffing into the pre-flop raiser here with the 5c a tainted out? It's bet, call, call, and I call.

Turn Qs

Things are looking much better now but I've already put a lot of money into the pot and I hate playing these draws. I check and it's bet, call, call, and I call. How weak was it not to have check-raised here?

River 5c

There it is, my tainted out. What's my action? Results to follow.