Despite the fact that you are in treatment and taking medicine, you family insists that you aren’t ill. It serves them to think that way. If they were to really get it, out of common decency they would have to stop leaning on you so hard. As long as they are dependent on you, they are unlikely to change.
My worry, though, is that you have bought into their analysis. Why don’t you mind the financial responsibility? You are only 27 and stressed to the max! Your whole system is telling you that you can’t keep this up. Unable to “police” yourself, you are, perhaps unconsciously, setting up situations where you are quite literally policed. I may be making too much of this. It could be that your meds just need tweaking. But in my therapist way, I have suspicions that there is more to it than that.
I’m concerned that you are focusing on what you can’t change instead of what maybe you can. No, you can’t change people’s attitudes when there is nothing in it for them to do so. But you can stop the gravy train. Unless your sister is so disabled that she is incapable of working, it’s time she started pulling at least some of the weight. Three years of doing the whole job is a long time for you to be the sole breadwinner. If she is disabled, please look into what kind of public assistance may be available in your state to help you out.
I hope your mom has been able to draw on unemployment benefits. I don’t understand why you’ve been taking care of all the bills for years if she was laid off only two months ago. That may be yet another conversation that needs to happen in the family.
Please talk to your counselor about how to shift your role in the family. If that’s impossible, it may be time for you to start working on getting your own place. You deserve to have a life.
I wish you well.