Well, I think we all have things we can work on, not that people are inherently unlikable. But I don't know your circumstances, so I'm not sure about this particular situation.
I think I understand though, I feel like that too. I spend 4 months straight alongside a group of women going through yoga teacher training, and I walked out without a single friend. I tried to make friends, but I'm pretty sure that I gave off some closed-off vibe or something because since the day I left not a single person has contacted me. I haven't contacted anyone either so that probably has something to do with it. I did ask one person who reminded me a lot of myself if she wanted to get together some time since we lived so close to each other, but she never reached out. Others in the group are basically best friends now..
Maybe you're giving off a certain vibe. I've learned that when you smile a lot, people are more apt to come up speak to you. People have told me I have a mean looking face sometimes. I'm not saying this is your problem, but I didn't even know it was mine until it was pointed out. Maybe ask a NT person around you to help point out the issue if it arises?
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-Diagnosed Asperger's