What was I thinking??

So apparently this morning I broke the cardinal rule (and didn't even know it). I was getting dressed for this short week, we have to work Monday & Tuesday then Teacher institute Wednesday, and my phone rings and I answered it. My ear hustling boyfriend who is still laying in the bed wakes up as I end my conversation:

Me: "Well I'll holla at you later"
BF: "Who was that?"
Me: "Trent"
BF: "Who?? Why is he calling you this early in the morning? He miss you or something? He always call you this early in the morning?(We had just made it back home after a weekend trip)"
Me: Super side eye
BF: "What was you talking to him about"
Me: "Nothing, He just said he was on his way home from work and called me. It's nothing."
BF: "Man did I come all the way down here so you could play me?? Just tell me what is going on."
Me: "Nothing is going on. He is a friend. NOTHING more. I told you about him. What you want me to do, stop being his friend?? What?"
BF: "Why did you even answer the phone? You saw me here. Why he call you like this all the time?"
Me: "it was automatic, the phone rang and I answered it. I didn't think anything of it. I have nothing to hide from you. Sorry. I really didn't think anything of me answering the phone. I keep the conversation less than a 45 sec."
Bf: "But you didn't have to even answer the phone while I was right here."
Me: "Ok. Next time I will not answer the phone."

So that's the start of the conversation, yes there was more on the ride to work. I keep my cool collective demeanor the whole time. I felt like I was a badgered witness!! Then he throws in, "ok I'm down with the conversation" only to start it back up four minutes later. I just let him talk. At this point, to me there is nothing more to say. Nothing I say is going to change the way he feels so why say it. I guess he was expecting me to go there with him, but I didn't. Wayyyy to early for that. And I am so not a morning person. Just get me to work!!!

So as I process the conversation now (although I have tons of papers to grade...been out for a few days because of having oral surgery) what the hell was I thinking??? I seriously didn't even think, I just answered my phone. I didn't speak in code or anything. Just said: "hello, getting ready for work, so you decide to call me this early, well I'll holla at you later." Oh and that reminds me, he also through in "So when are you going to call him back, on your lunch break?" By then I was heated, literally boiling on the inside! But I keep my cool. I was proud of myself for that. So I guess the lesson learned is don't answer the phone and I won't...