Overreacting

Hay

So I have been talking to this guy for 5 days, I repeated only 5 days. We spent everyday together for those 5 days. And yesterday I hung out with another guy and didn’t tell him and I went over his house later that night to ask the “dtr” question and he said “ i thought you were my girlfriend” I said okay, I just needed to know”... he then asked if it was because of another guy I remained silent. then he BLEW THE FUCK UP got so angry and was like I need to chose right now him or the other guy!!

He is overreacting or am I being insensitive?