Hey there, JF. Welcome to the boards.
I'm sorry that you've been feeling the way you have been. Feeling like you're disliked or like you're not accepted for things about yourself that weren't your choice -- like your ethnicity or gender -- absolutely sucks. Feeling liek you don't belong anywhere is so isolating.
I think that a few things are probably happening here, things that have been bringing up these kinds of feelings for a lot of cis gender white dudes (some of whom aren't handling it as well as it sounds like you are).
For one, as we inch towards equality for everyone -- a slow, painstaking process, but one where we've had some incremental progress, at least -- that means that some of the way the rest of us have been seen or treated is also going to be some of the ways that cisgender white guys are seen or treated. And as things gradually change and white men aren't both at the top and in the center of everything, I think that is going to feel some kind of way, even for younger men. I still think that both culturally and usually in families, there's an implicit (though probably unconscious in many ways for younger men now) expectation when you grow up as a white guy of a certain position in the world and a certain way you'll be treated and seen and when that expectation isn't met, it tends to result in some of the feelings you're expressing.
Of course, it's trickier when you're marginalized in other ways, like by being bisexual. I can get how it might feel in some ways like you can't fully fit into or be accepted in any of the possible worlds you walk in. I'm so sorry about that.
The good news -- if you can call it that, anyway -- is that a lot of us really do understand some of how you're feeling, because again, some of the things you're voicing have been how things have been for the rest of us for pretty much ever. So, you do, I think, have opportunities to connect with people who can relate in a lot of ways, and who can share some of how we've learned to cope with similar feelings of not belonging or of facing bias.
Of course, another thing at play is that a lot of cis white men have behaved truly atrociously through history and still are now, some worse than ever, some downright dangerously or violently, in part because they're reacting to it no longer being a given they'll get all the privilege really poorly. Again, this doesn't sound like you, and you're certainly not responsible for the behaviour of other men. But you can perhaps understand a lot of people's feelings around some of these other men in the past and present.
That doesn't mean you have to accept people painting you with that broad brush, but I do think it's helpful to try and learn how to engage with people having those kinds of feelings: it's good that people are starting to hold men more accountable, after all, and it's also not a problem for men who WANT to be something besides horrible assholes. I think if you can learn to listen to some people's feelings and thoughts about all this, to hold some space for this, you'll feel less shoved out. I can't speak to doing that as a man, but I can speak to learning to do that as a white person, if you want to dig into that some more and in a personal way.
Can you tell me a little bit about your own social world and community? For instance, is there anywhere you DO feel like you belong right now? Friends? Family (be it the one you inherited or chosen family)? School? A GSA? Some kind of community outside school? If the answer is in none of those places, can you fill me in some about what the barriers feel like?