Am I being ghosted?

Hi everyone. I’ll try to keep this brief but just as an overview, I’ve been dating this guy for the past 6 months. Early on we went on dates and the energy felt mutually exciting. As things progressed, the energy became lazy and things started to feel more casual. Last week was normal- no red flags. Conversation as normal. Over the weekend we had a mutual friend’s birthday party and he called me to try to coordinate us going. I had a work event pop up last minute and wasn’t able to attend. That night I called him, but he never called me back, which was weird because up until now he always returned my phone calls. I brushed it off. The next day I don’t hear from him all day, also odd. I call him and we chat for about an hour. Everything seems fine. The next day, no text and no call and also the following day after that, silence. I no longer want to initiate because he clearly lost interest. But should I prepare myself for him to never contact me again? Or is it still too early to tell? Also, if you were in this scenario, what would you do?