That sounds kinda wonderful. Ok, not the anxiety and feeling like you'll be crushed if he doesn't like you part that sounds blah and very stressful.
But liking someone is nice.
And, the person liking you going out of their way to engage with you sounds really neat.

Hmmm, I know you're saying this is hard for you and I hear the anxiety. Still, I've got to admit I feel a little envious of your situation.

Do you have any grounding or mindfullness techniques that might help you not get so flustered?

Dating co-workers can get a bit messy but I also think it can be a good way to get to know someone. You get to see how he treats other people, what his work ethic is like, does he use humor or compassion or does he listen well? It's an opportunity to see if he's really what your looking for by observing how he interacts with others

I think butterflies are pretty even when they're in the tummy.