I'm sorry things haven't been going as well as you'd like guy. I think the root issue here is how you've taken up your families issues as your own - at least, I know that was a main cause for my concerns years back. After my dad passed away, I shifted gears and started focus on taking care of my brother and mom over anything and everything else. I, too, was starting to "wear thin", in every conceivable way.
It wasn't until last year when I decided to shift gears (again) and focus on myself first and foremost. Man, did it have one hell of an impact on my life. The result was me being happier than I've ever been --- and it started to affect other people around me too. All of a sudden my relationship with my mom and brother started to improve, as did their moods in a general sense. My brother started to get more productive, as did my mom. All of these incredible things started happening for me -- and it was 'not' just a coincidence. Something I wrote a little while ago ties into what I'm saying pretty well:
"...I genuinely believe that when you're in a good place - when you're happy, people can tell. Your words end up having clarity and depth to them, and even the simplest ideas and concepts end up having a profound effect on others. And when you're good to others, they'll be just that much more likely to be good to someone else as well. In its simplest form, to make the world a better place, find what makes 'you' happy, make it happen, and "Be the change you wish to see in the world".
Anyways, It sounds to me like you're putting "the weight of living" on your shoulders, and it's taking everything out of you (as it did for me years back). When things are tough, every other issue seems magnified ten fold (aka, much worse than they actually may be). If I could offer you any piece of advice... it's to break the cycle. Change things up, live your life 'for you'. If money's an issue, maybe it's time to speak to your family about a more realistic solution (finding a cheaper place, or whatever else you deem to be a solution). If they can't find a way to understand that you're not happy with the current state of things... they don't have their priorities straight. Because I'm telling you man, NOTHING is ever worth giving up your happiness. It's so easy to forget, amidst our lust for "things", that happiness is the root of 'everything' in life. It's what drives us to go to school, to date, to work, to travel, etc etc. If you lose that... what's the point? That's where the suicidal thoughts start to stem from.
What you've been doing for the past two years... it clearly isn't working. If their attitudes haven't improved, if yours has gotten worse, etc etc, then it's time to change things up brother. Get away from this "cycle" you're seemingly stuck in, start going back to school (it sounds like it's something you want to be doing) and get out of the house more - away from the negativity. Because the lonliest feeling in the world, quite honestly, isn't being alone. It's being surrounded by the wrong people. And the wrong people are those that don't make you feel fucking phenomenal (regardless of who they may be).
Anyways, I hope that helped. Don't expect anyone else to step in and help you out of this, re: those in your life. 'Your' life is, quite literally, in 'your' control. You "can" be happy (again). Now go out there and make it happen man!
Oh, and PS:. Say your family doesn't respond well to the idea of moving into a cheaper place (or your dad stepping up, assuming he hasn't been trying to find work). It does not make you a bad person or a bad son to take life into your own hands and step away from them for a little while. Just as your life is your own responsibility, so is there's. We should all be there to help each other out, but to blatantly take advantage of another person -- it just isn't right. And I'm sure they're not doing it on purpose, they've just gotten comfortable (complacent even) with the current arrangement (stuck in the cycle, haha). At the end of it all, when you strip away all the variables... all they want is for you to be happy. And whether they understand that now or not, they'll get it one day. So do what's best for You man.
"..know that you are always moving, even when you think you are still. that even when you think you are going nowhere, you are going somewhere. and if you stay in one place too long, you body will resist. it was not made to be stagnant. it, like all bodies of earth, water, air, life – needs to be in constant motion. "