Hi Solo, your generosity has cost you dearly, and you have your retirement to think about. I understand how difficult it is to say no when people expect you to pick up after them, but it's essential you pull yourself out of this mess.
Have you considered going to a financial advisor and getting a plan in place to see you through the next few years? I believe you have as big attitude problems as the sponging relatives, although your thinking is destructive (to you) in a different way.
Once you get professional advice and a plan, put it all down in a statement that spells it out for the relatives. Part of the plan is that you can no longer spend on supporting them, and this is the reason why. Ask them to read it, then if they understand it. So they have clear notice that you cannot give them money because you are in debt and need to work on that.
They will ask a few times more, but at least you can refer them back to your policy without getting into arguments. Do not give in, no matter what they tell you. You can do this if you plan it out and work around your difficulty in saying no.