Over analyzing can be a problem if you let it. Sometimes there are no whys, things just happen. We like to think we live in an ordered world, but some things are just random.
You are already in therapy, so you have someone to bounce ideas off who has no agenda other than helping you work your way through what is bothering you. It might help you to keep a journal about your feelings. Putting down how you feel each day about your body, which gender you identify with etc. One of the hardest things to do when you are in the middle of a difficult decision or position, is to trust your memory. "Did I really feel like that last week, or was it the week before?". If you write things down, you can go back and see where you were on a given day and not have to second guess your memory.
Sometimes when things get too heavy, we just want to be normal, even if it means trying to live in the gender we don't identify with. I can remember dating a couple of guys because I just wanted to fit in, to belong, then feeling depressed afterwards or feeling embarrassed if someone I knew saw me with a guy.
Give using a journal a try. It may help you, it may not, but it can't hurt. Its also useful in remembering what you want to discuss with your therapist.
sam1234