Is this the No Contact?

We used to talk much with my male co-worker. He sent me messages. We grew to like each other. Suddenly one day he ghosted me on messenger. We haven't spoken at work since. I don't understand what happened. He doesn't even say hello anymore. And many days go by without seeing him. He avoids me. I was the only one who existed for him at work. Now I do not exist for him. He doesn't seem to like talking to me. I can't ask him. What do you think?

Is this the No Contact?
Post Opinion