Jessica,
I absolutely know where you live with that anxiety. I have been seeing a therapist and it seems to clarify some things but I have yet to come out to my wife and family. Not trying to compare, just for reference.
I am also constantly questioning the validity of my thoughts about being MTF. Maybe it's just dropping of androgens as I hit middle age and am having a crisis.
I guess I keep coming back to the question if it is "just depression" or a midlife crisis would the logical conclusion be I'm transgendered? Also where in those arguments would past history of dressing before puberty or other personal leanings come from?
I don't have full answers for you or myself. I think the thing is to keep trying to make sense of it all, be true to ourselves and love and support those around you. I am finding fear, resentment and blame are enemies as are most negative emotions. Sure, we have to go through some of them but trying to move beyond them. I feel a little hypocritical saying all this when I live in fear at the moment.
Guess what I'm really saying is, I feel for you an empathize. I think most of us here are in/or have been in such similar instances.
I wish you luck.