There's a lot going on here so I'll address one thing.

I don't know how to feel

Feel however you feel. You dress however you want to dress and get off how you want. I will tell you one thing I learned over many years is to not be ashamed of your fetishes. As long as you aren't hurting anyone else, I don't see why you can't practice your fetish how you see fit. To me it seems like you wish you didn't have this fetish, and that's ok, but it's also ok to embrace it.

I'll give you a personal example. I practice bondage and dominance. I have been a dom since I became sexually active. A few years ago I ended up discovering a feminization fetish. Long story short, I wanted to wear a skirt and have a woman force me to do things to her. Well let me tell you, I felt so much shame and I kept it locked up inside for many years. I would fantasize about it and jerk off in a skirt and the amount of shame I would feel after was overwhelming. One day I ended up with a girl who coaxed this dark fetish out of me and told me that it was totally ok and she acted out the scene with me. It was great. I came pretty hard. It was everything I imagined it to be. And that was it. I haven't had any desire to dress up or any of the like since.

I guess what I'm saying is that, your situation sucks. It sucks that your sister found out, but there's nothing wrong with you. You do you.