One other thought, if you aren't too fed up with being dissected here. I wonder if the bright colours/juggler/busker look may not suit you? It makes quite a statement, and one has to have the right kind of personality to carry it off. Given that you are naturally a bit shy, perhaps this sends mixed signals that can be interpreted as "creepy"?

I have another male friend who always comes across as insincere to me, because his mannerisms are very "lovey" and affected (I don't mean this is how you are, it's just a somewhat comparable case). I have it on very good authority that he's completely genuine and is just overcompensating for being underconfident, but I still have trouble relating to him.

So you could try wearing smart, normal clothes and making sure you look well groomed. You're an IT professional, and that style of clothing can be a perfectly good look for everyday. Maybe that would help you feel more comfortable, and if you do have a shy moment, you can just go with it, instead of feeling you have to perform/trying too hard?

Of course, these comments don't apply to when you ARE in costume, e.g. at a LARP, con or costumey party. Then, go for it and indulge your love of dressing up!

Anyway, just my 2-p's worth, I hope no offence taken as none intended. I think you're a lovely guy and deserve better.