Hunni, you've been saying that you will leave if she starts so many times. I know she's your sister, but there has to come a point where you put you first.
Why don't you check in a bit more often? You might find it really helps to keep talking and to also talk through options of what happens with her etc...

Are you stopping the vort under the supervision of a Dr? How long were you on it for?

None of these options are going to make you feel better overnight, or in a months time. You have to use all of it for a sustained period of time. You didn't get this poorly overnight, so it's going to take time and self care, support, right therapy options etc to get you feeling brighter.....