God, you can all flame me for my stupidity.
No OP - we shouldn't.
You've made a mistake, recognised that you were being taken advantage of, and have taken steps to rectify the matter.
You know you were foolishly indulgent with her, but that's in the past. Don't beat yourself up. You have been MASSIVELY COURAGEOUS to tell your DH, and to take a stand against your sister.
It's not easy. You love her and feel responsible for her because that is what life taught you to feel. But you aren't - she is a grown-up, and now you recognise that your DH and DC are the important things.
Anything life-threatening, of course help her out again. Any financial worries - and that includes re=possession and/or bankruptcy - are HER and her DP's responsibility.
I hope you get at least some of your money back, but if not, just let that phase of your relationship go and don't let it eat away at you.
Anger is good if it prompts you to take action, which it has; if it becomes bitterness and resentment it will ruin you life. You deserve better, and so do your DH and DC.