Correct Pot Odds vs Survival Right Now

[stuartharris]

I'm sure that this has been covered here before, but I've run across a situation several times in the last week where I'm not sure how I should proceed.

I flop a flush draw or an open-ended straight draw. Someone in front of me bets 1/2 pot or so and gets a couple of callers before me. I call.

I miss the turn. Again, someone in front of me bets 1/2 pot or even less and gets a couple of callers. I'm getting 5:1 or so and call again.

What should my thinking be in these situations? Having played a couple of hundred thousand hands of limit, I'm accustomed to playing these hands, knowing that, in the long run, I'll make money. Should that be my thinking here as well? Should I assume that "it's all one long session" and that I'll hit often enough to pay off in the long run? Or should I acknowledge that I'm more likely to miss than hit on this particular hand and that playing, even with correct pot odds, may cost me half my stack and put me into a position where I can no longer play my good game? I'm aware, for example, that the chips I'm gambling are more valuable than the chips I stand to win in this situation.

Can anyone give me insight into how to handle this situation? Has someone developed a reliable method of evaluating "the real pot odds" (perhaps there's a more standard term that I don't know) for this situation?

Any help will be appreciated.