i can see your sacrifice, your utmost care and respect for your family and your pain too. at some time in my life i was at the same point where you are right now. there was a time i sacrificed for my family like the way you did....always put my family's need first and put my own needs second but for everything i did all i received was 3 years of depression, the depression so intense that left me to the point i lost all my hope for my life. reminds me of a linkin park's song "In the End" especially this phrase "I tried so hard and got so far but in the end it doesn't even matter".

but lets get real...

if you are thinking that your brother and sister will help you back like the way you did, i would say please don't expect anything back from them unless your brother and sister think in the same way as you do. you created this mess, you are in this mess so you got to solve it. its possible that they might not help you at all so be mentally prepared to face that too. I would advice you to explain your situation to your family and be clear and see what their responses are....if they truly appreciate your help and sacrifice they will help you back, if not they will back off. 

The fact is don't think too much about it. thing how you can get yourself out of the mess You have done everything you could and you have successfully fulfilled your responsibility, feel proud and good about it. Now let them complete theirs. If you start expecting from them and you don't get any, you will get depressed. 

good luck for your future