I remember those feelings - they still happen to me sometimes, but as time continues it becomes less severe and less frequent. Mostly what helped me in acute & distressing moments was to sit down and analyze it by writing in my journal - walk through what the possibilities were, what reasons I had for taking HRT, etc.

What I realized was even if I'm not a woman, even if I'm doing it for the wrong reasons, the objective reality is that estrogen was really helping me, and testosterone seemed to really harm me.

It was also important to recognize the alternative to being a trans woman is that I'm a cis man who has somehow confused himself, and when you consider the question "are you a cis man" you have to ask yourself if you prefer to have a male body, prefer to be a man socially, etc. - it became clear to me I certainly wasn't a cis man ... what is left is that I'm either non-binary or a trans woman, and everything about being a woman sounded great to me - I wish I had been born a cis woman. When I journal it out that way and look at it objectively, it's hard to deny if I were anyone else I would think they were a trans woman, so that's probably right in my case, too.

I remember especially feeling immense doubts and fears right before my orchi, because it felt like a huge commitment I couldn't possibly reverse. A therapist of mine once noted that I should recognize that either way is a commitment, if I don't take HRT or get surgeries, then I close a door on the life I could have had if I did take HRT and got surgery. That helps - inaction is not a default, it is not safer or more reasonable - inaction is a choice with long term consequences just as taking actions like HRT or surgery have long term consequences. The question is which consequences you wish for, what life do you want?

Congrats on taking the first step! That's the hardest one. I struggled with similar doubts for the first 2-3 months of HRT as well, but ever since, there's nothing I'm more certain about in my entire life.