I know now that I can't share real information with her especially about my real heartfelt issues
I think this is a good place to start.
I also think part of the problem with your siblings, including your sister, is that you all have certain roles that were established long ago and those are continuing now that you are adults. It happens all the time and trying to shed that role takes a lot of work on our Self. How we look at our self, how we look at the world and our relationships in it, and how we respond rather than react.
I guess I just need help on where to go from here?
I think you are on the right track in terms of trying to udnerstand the relationships as they are. Focusing on you and your own behaviors and learning tools to help you cope and to differentiate from your family will go a long way in terms of helping you feel better about your interactions with them. You can learn better ways to respond, you can also learn about boundaries and all of that will help even if you do decide to walk away.