maybe if you met some other guys (single) you may be able to work out your feelings,
sometimes when you start working closely with another person you can develop strong feelings. especially if your feeling down or a bit insecure.
If it were me I would stop focusing on the flirtation/eye contact/does he or doesnt he issues and try to keep things in a worklike manner, your feelings may subside
on their own, go out and meet people, it does wonders for putting things in perspective