(((((((EJNT)))))))))
I understand how difficult it can be to meet people in your 30's and beyond. I found too at one point I was only meeting people at work and had stopped any outside interests for other places to meet people with common interests and activities. Dating at work in general has serious pitfalls. Sometimes they can be overcome but I've seen that it is best to keep dating and professional separate. However, being asked out by a coworker is not a reason in my mind to make things so uncomfortable between us as to leave my job, unless the job itself is problematic or there are harassment issues (which does not sound like the case

).
I wouldn't attribute their reasons for not going out with out with you as necessarily personal reasons against you. They may have legitimate reasons that you cannot know for certain or concerns for dating in general at the moment, are not excuses and have nothing to do with you. However, even if they are excuses, you deserve to have your feelings returned and will find someone who does. That doesn't mean you should rule out relationships with these people. Some of my best relationships began as friendships, even with coworkers, with no expectations of romance; not having this pressure really allowed us to get to know each other, romance bloomed in some cases and lasted. The friendships also led to meeting other acquaintances of their's and romantic relationships. Just as in business, networking is important for dating.
Lots of us are looking for someone special in our lives and know you are not alone in this. It's important to keep an open mind for people and places to be, know your interests, to be honest, and to get out there. You are worth it and do deserve it.