These things aren't going to solve your situation or make all of the problems go away, but try to keep them in mind:
1. Who says you're going to end up alone? That's not something worth stressing over. Do you know anyone who can predict the future? I don't. Life is strange, and unexpected things happen every day.
2. Let's say you want to date a girl, get into a serious relationship with her, and one day you hope to get married. With this in mind, statistically, most girls you meet are "the wrong person".
3. Trust me, no relationship > a bad relationship. When you meet a girl you like, what is it you like about her? Is it that she's a female who you think will date you and understand you or is it because you are drawn to her as a person? The first one's a logical thought process; the second is emotional. If a girl is drawn to you emotionally, you won't have to 'convince' her to date you. That is definitely worth waiting for.
4. If someone doesn't want to date you, there's a good chance it has nothing to do with the way you act, look, or dress. I, for example, have several male friends who I find attractive, funny, smart, and fun to be around. But I would never be attracted to them in the sense that I'd like to date them.
5. You're young, and you seem like a smart, interesting guy who obviously thinks about the consequences of his actions. I know this sounds like generic advice, but the less you worry about dating, the easier it becomes. I suck at dating. The more I analyze it, the more I feel like I'm going insane. Thankfully I haven't had to worry about it since I met my boyfriend.
6. You can't force things to work out, try to stop stressing over what you have no control over. Much easier said that done, I know. But I guarantee you that probably 99% of humanity, not just aspies, feel the exact way you're feeling at some point. Clearly most of them don't end up alone.
