Surreygirl... don't make me come round there and insert a foot up your a55 as it would a) hurt and b) upset me as I'm very passive aggressive.
He (and any other bloke) will most certainly think 'yuk' if you walk around thinking like that as it will come across in your body language, the way you speak and how you hold yourself. I've read some of your threads on here before and you almost seem to be apologising for breathing... STOP IT!
You sound like a nice, attractive girl who makes the best of herself at all times and is always keen to smile. Walk around thinking that instead and hold your head up in the knowledge that you are. If that bloke in your office is with someone else, so what, his loss. If this bloke doesn't respond, big deal, there are others that will.
And before you say that this is easy for me to say, I am not the perfect size 10, pretty far from it actually, I do not have men flocking around me at all times, I am not coupled up, or below 25 in the age range or anything special looking. But I do think I'm a nice person and worth talking to. So should you.
And don't worry about when that someone special will come along, they'll come along when you least expect it and not when you go looking for it (so I'm told).
Right.... < Big Hug> .... Don't make me have to do that again young lady... hold your head up and stop worrying xx