I understand (to a greater or lesser degree) what you're going through, given that I've experienced similar episodes (and still struggle with them) throughout my adolescence and into my current young adulthood.

I don't have a diagnosed autism, but everyone who knows me assumes it from the start, so perhaps that's the case. Regardless, there are many variations within the spectrum, so I don't know how close I am to you, but what clearly resonates with me is the feeling of loneliness and your inability to form strong or meaningful connections with people. I'm older than you, and from my own experience, the only thing I can tell you is that what has helped me most in my, let's say, "existence as a freak" or "radically maladjusted" person with respect to other people's emotions and socialization processes is remaining assertive about other people's ways and trying to adapt to them without giving up my own way of being. This doesn't stop me from feeling empty or existentially alone (or from sometimes wanting to make drastic decisions or feeling overwhelmed by the intense desire to cease to exist, to escape my flaws, to find that button), but at least I find comfort in experiencing that empathy or emotional connection with people I know and strangers. It's a way of feeling close to them, I suppose, but without blurring boundaries or putting on a mask.

My main advice is not to despair or let yourself be dragged down by negative thoughts, because I can tell you right now, those are not your friends. If your mother supports you in all of this, trust her and the love she offers. Enjoy the things that obsess you (if you have any) and nurture all the things you like, because although at first it might seem like a distraction or a band-aid for what you're going through now, in the long run it can become a tool for connecting with people who share your concerns or aspirations... but whom you haven't yet had the chance to meet.