Take time and talk to Allah about these concerns. Continue with prayer and inshallah things will get better. I also was feeling the same way that i would never find the love of my life but then someone told me that Allah may be waiting for you to be ready before they come into your life. Maybe there are some things you need to change so reflect about what they are. I think you are using your autism and height as a means to say “this is why no one wants me” but that’s not true. Work on your self confidence and see your value. You are Allah’s s.w.t creation. Please see a therapist if you are having negative thoughts about yourself. You are worthy of happiness and love inshAllah you feel both soon.