Wow, it sounds like you and your family are going through a pretty rough time. Good luck with it all.

It can be very frustrating and lonely when a sibling has a problem that takes up a lot of attention and everyone in the family is focused on that issue. I can understand why you would feel lost, as everyone is focused your sister's issues.

But you may want to consider getting involved in the family therapy and meetings if you haven't already--you could probably bring up how you are feeling as it comes up in the sessions. Part of family therapy is learning about how family members deal with one another, and your feeling lost is a valid point. Having everyone hear about and discuss how YOU are dealing with this family situation can be a good way to help begin solving the problem, even though it's your sister's issues that brought you into the therapy sessions in the first place.

If you don't want to go to the meetings, it's totally fine. You could also decide to go to only some of the meetings if you have time constraints.

Whether or not you go, you could still try talking to your parents--either separately or while they are together--about how you are feeling. If your sister is staying in rehab while you are living at home with one of them, you may be able to find a time at home when you could bring things up. Or you could try writing down how you feel in a letter or journal to one or both of your parents and, if you feel like it, show it to them if you are uneasy about starting the conversation.

Also, you may find that just writing down your feelings makes you feel better, and you may figure out how to approach your parents in a way that feels most comfortable for you.

Just because your sister is the one in rehab doesn't mean she is the only with valid problems and concerns. At the same time, coming together as a family at this time to support your sister may help strengthen your bonds with your parents, and ultimately bring the entire family closer together.