Also, I just want to add, transitioning changes EVERYTHING.
I spent almost all of my high school and college years barely having any friends, feeling completely shut-in, completely isolated, constantly thinking self-defeating thoughts like "no one would understand," and like "if I ever told anyone, they'd laugh me into an oblivion and call me names, and I'd be even worse off than before," almost failed out of school three separate times despite also being one of the smartest kids in the entire school, and just never feeling comfortable around other people, never able to live up to my potential, and a host of other things where it just seemed like everything was crumbling down around me and I didn't know what was wrong.
And let me tell you, after less than a month of HRT, EVERYTHING has changed. For the first time, I actually have a sense of self. I'm actually happy with who I am. I actually feel confident talking to people, and actually have the energy to go and do things, and I FINALLY feel like I can be myself... be silly and spontaneous, and laugh, and actually show real emotion instead of just constantly hiding it and just feeling like crap all the time.
I know this is just one person talking, but seriously, a lot of these problems that you are describing... the fear, the lack of "mental energy," the frustration and hopelessness, those very well might all change. I felt a lot of the same feelings when I was just graduating high school. But now, 7 years later, I've discovered that almost all of those feelings were caused by my gender dysphoria. And once I started transitioning, it really was like a complete revelation. Problems that I thought had absolutely nothing to do with my gender identity, problems that I was so sure I'd never get over as long as I live, actually ended up getting better!
So don't give up so quickly. There IS hope out there, and you may be surprised at just how much transitioning can make your mind finally feel right.
