Definitely complete on 3rd. This is a huge raising hand. If it was already complete, I'd reraise. All of those callers aren't going to fold after calling the bring-in. That's how you make money, by pumping up the pot when calls are likely and you've got the best of it so that calls aren't scary.

You hand was never obviously terrible. In fact it wasn't terrible in the least. You EV started at 40% and increased each street all the way to 79% on the river (keep in mind that this is against random hands and the flush draw guy isn't a random hand. Bet bet bet. You played it well except for the missed raise on 3rd and possibly a reraise on 5th (though with the flush raising I might save my raise for a sign of weakness).