First and foremost, I hope the support you find here gives you hope and lifts your spirits, even if it doesn't provide the solutions to your problems. Never forget that your emotions, including self loathing, doubt and despair, are valid because they are human emotions. One thing you can be sure of, especially on this forum is that YOU ARE NOT ALONE!
Self loathing and self hatred take many forms and for many different reasons. This is a problem faced by many people, not just those that are GBLTQ. There is nothing wrong with self doubt. It means you are thinking before you act at the very least. The downside of self loathing is that regardless of your chosen path, it is impossible to truly be happy. If you are not happy with yourself, its extremely difficult to make others happy around you, especially a significant other.
Regarding rejection: For one reason or another, I've had over a hundred failed relationships (counting high school ones) and even a failed engagement. I've been rejected hundreds of times. It took decades of becoming comfortable with my self and waiting for someone that will accept me and my flaws to find the love of my life. We've been married for 13 years now. Rejection always hurts and can cause anxiety and fear. One way to overcome that is to take on the mindset that if they reject you for a superficial reason (such as your physique,) they weren't good enough for you in the first place. There is someone out there for you that will accept and love you for who you really are, regardless of your transition status, as long as you treat them right. It just make take a while to find them.
No one but you can determine if transitioning or de-transitioning (and yes as long as you haven't had bottom surgery, it's possible, I've had to do it myself at one point, starting over now,) is the right path for your life. While those pesky "What Ifs" can provide insight and inspiration on how to proceed in the future, no one will know for sure if they would have had a better outcome. All you can do is control what you do in the present. Transitioning and being LBGTQ is always going to be a harder life than straight cisgender. I don't know that any of us wished for the added difficulty. But as with most things in life, the harder the struggle and the more patience required, the more satisfying the outcome when you finally succeed. If your true self is "male" then that may well be your path. There are also plenty of transgenders that either don't transition, or stop part way for a multitude of reason. They are all valid in their choices. What works for one may very well be the worst course of action for another. We are all here to help with the obstacles you face, so don't give up hope. Do us all a favor and look in the mirror, tell yourself that you are valid as a person, people love you, and give yourself a hug. Stay Safe.
HUGS!