I'd say the best thing to do is figure out you. Everyone else has already put in the best advice they could for you—now it's up for you to put that together, if you like, and figure out what works and how.
You can go on dates, test waters, allow yourself the freedom of friendship. At this point, I personally don't think it's healthy for you to jump into any serious relationship, but you may think differently. Discovery more of self other than appearance and reliance on others is as good an endeavor as any, especially if you wish to foster new relationships, no matter who they're with. You are you; they are them. The real challenge is figuring out what "you" means without the attachments from other people (though, as was said, a long-winded quest of self could end in shit).
If people make assumptions about you that have no real basis, that's their problem. You certainly don't put off any asshole vibes. Sometimes people misinterpret what they're seeing or hearing, and confidence means different things for different people. Every person has their own line for where "overconfidence" begins and that is, again, not your problem.
I don't know where I'm going with this.