RE: More stress? Say "No, thank you!"
It is off course a very tricky trail and as you say, with todays stress you might find it as overwhelming as anything else to be the one that supports everyone else to. That shouldn't be the case either; it will be that ones source for stress.
At the same time; we have so much going on around us and so many "needy" people that you should be wary to keep the ones that are on the positive "supportive" side of you and stay distant to the ones that are on your negative "needy" side of you.
I have been in that very position. I haven't "cut" people off, but I've put them aside because they don't add to my positive side at all. They take out more of you than they give back; and that's a reason to let them go, they aren't the people that you need around you.
I'm sorry to hear that you've experienced that. But I suppose, at some point, everyone is bound to meet the "negative" needy. I've learned the hard way and it had been a difficult process for me to minimize contact with those that drain me more than help me. Thank you very much for you insights!