I recently decided to contact a guy I had worked with to see how he was doing. I called his job and left a message for him to call me along with my cell phone number. When I checked my phone later in the day I found five call backs from him, the first coming fifteen minutes after I left the message for him. He called four more times in the next hour and a half, leaving his cell phone number as a call back number. He called again after work and this time I answered the phone. I expected him to say something like "hi. How are you doing?" Instead he said he did not know who I was. What is going on? Could he have forgotten me that quickly? It was only about four months since I last saw him. Is he playing some kind of game? I was so stunned at his reaction that I did not know what to say. I simply hung up. Should I call him back or just forget about his strange reaction?