Moving on with Facebook?

I found this guy really attractive at work and well he found out through coworkers I liked him to. Upon discovering that he began sayig hi, smiling at me, doing things for me to notice him. BUT I had just gotten out of a terrible terrible relationship so when he began doing this I FREAKED and like ran away. I could not look him in the eye or even be the first to say hi because I do not know why I am scared.
Anyways eventually he thought I lost interest and stopped giving me attention :(
Now I regret it a bit. I know I need a break from dating to recover from my last relationship but I really like this guy. However he is also a co worker.
Should I add him on fb as a step towars talking to him or just leave it alone and ignore my feelings towards him?
P.S. My last boyfriend really lowered my self esteem and was emotionally abusive which is why I was afraid of this new guy when he showed interest in me.