I would have said you probably have Obsessive Compulsive Personality Disorder which seems more about the obsessive and intrusive thoughts than about compulsion, per se. I'm not a doctor, though.

I think it's simply that you are more sensitive to social norms, like now that your sister is older, she should dress by herself in her own room or bathroom. You may simply be over-worrying it. And dragging it out into the light of day like this is a step in the right direction of relieving you of that worry.

Staying away from your family is not the best idea, either. They're your support network. I think if you talked about this with a professional therapist, it might help a lot in reassuring you and making you feel better about who you are right now. That's really all that matters: This moment, here and now as you read this. Who are you right now? Who do you want to be? That is all you need to focus on, and let the past (your past sexuality issues) bury the past. All that matters right now is that you are someone who is concerned, and in need of support and reassurance, I think.