Are you sure? I would say this then:
Take a week and look for as many signs of interest as you can directed at other men. See if you can pick up on these.
My guess is once you start seeing them aimed at other men, you'll begin to notice them aimed at you too.
I've taken a lot of guys into the field, including a lot of guys who are not remotely conventionally attractive... often these signs are invisible to them, and they insist they don't get them. But I am still able to find girls who signal them anyway (not always the cutest girls, though, especially for the really out-of-shape, schlubby guys... but I do find them), and send them in.
If you never, ever get signs of interest, I've yet to meet a guy that's the case for -- it is always, in my experience, 100%, down to the guy not seeing them.
Hard to say for certain without going out with you in person, but IME it's always down to "guy doesn't recognize the signs", rather than "guy gets no signs whatsoever."