My guy friend has got the same problem as you. And he is as straight as you can get. But what makes people think that he is gay, is his voice, the way he talks. I have to admit, he does sound a little flamey. But again, he is totally straight. Maybe you should ask a close friend, someone that will give you an honest opinion. These people that you work with, you just met them. They're not gonna tell you that you're voice or the way you walk is feminime. But then again, they did ask you if you were gay, and I think that was going a little to far and very insensitive.