While some trans folks say they "feel" their gender, there are many of us who don't. I have no idea what "male" feels like, nor what "female" feels like. I only know what I feel like: I feel like me. I have nothing to which to compare the feeling of being me. I don't have a male "before" and female "after" to compare, since biology tells us that gender has a biological basis: I have always been female, I just didn't realize it.
I only know that, since I started transitioning, I feel happier about myself. I was asocial before, now, I happily mingle with other women, though I still have a lot to learn about the way women process interactions. I feel like a huge weight has lifted from my shoulders.
It is normal to have doubts. We all have them. One of the best things about transitioning is that it helps you to remove some of the doubts. Unfortunately, that is something you can only experience after you have started.
My doubts, when they arrive, are usually along the lines of "Life would have been so much simpler if I wasn't transitioning. So maybe I'm not really trans." But there are a few things I tell myself to get past them:
- Simpler does not mean happier. I am definitely happier now.
- I was not able to stop cross-dressing pre-transition. It was a need, not a want.
- Never in my life, not a single time, did I ever wish to be more masculine. On the contrary, I always wanted to be more feminine.
- Even when I thought I was a guy, I wanted to be a "soft" (i.e. feminine) male.
Those are all facts that, even when things get confusing, I cannot deny. They all point to the same conclusion.
You might want to try making a list of similar signs for yourself, to help you weather the doubts. As you progress and accumulate experiences, your doubts will grow fewer. Remember that cisgender people almost never thing about their gender. Trans people are almost always thinking about it.