Should I hook up with my co worker.

My bf broke up with me three weeks ago because he said he wanted to focus on himself and not ready for a relationship. I was devastated.  We been together for four years and I still think about him sometimes. I don't want anything serious and I do find my coworker attractive. I do want to hook up to make myself feel better, but at the same time I feel guilty about it. I feel like I'm still in the relationship with my ex even though I don't talk to him anymore.