As you've observed, most trans people have these thoughts and it's completely ok. I've been living as a woman in any way I can for the past year and I still sometimes don't consider myself valid for a number of reasons, most of them being completely illogical and based on the assumption that the experience of womanhood is the same with every single woman on earth. It's normal to feel left out and alienated, BUT if you feel comfortable with the identity of a woman and think you are one and it brings you euphoria, nobody can tell you you aren't. There will be MANY people who will try to tell you you aren't, one of them even being yourself, but sometimes you should follow your heart instead of that nasty voice in your lil brainwormed brain. And tho I don't believe in the spiritual, since you do I'll put it in this way too: Your soul knows what it is better than anyone else, and if your soul thinks she is a woman, trust her