I feel like this a lot...probably because I'm still pre-everything, but it goes away more often when I'm alone. Not so much around other people though. It's why I had to stop living full-time; between all my masculine bodily flaws, still being called "he" (by people I know), and paranoia about getting clocked, I couldn't help but feel like something someone stepped in...like I deserved put-downs for looking not like a girl, but a "boy who wants to be a girl".
I still wear feminine clothes most of the time, but I admit to everyone around me that I'm biologically male (use the boys room, allow people to call me "he", etc.) I haven't decided if I'm being more genuine to my current situation, or less genuine to myself, but it does stop making me feel like a "pretend girl" because I'm not fighting the uphill battle of completely passing.