What does it mean when your ex starts calling you your old nickname he gave you?

My ex starts calling me buzz which is an old nickname he gave me, we have been talking as friends as he initiates every conversation. The conversation usually takes place at night, weird hours. He will start the convo by saying Buzz you awake? Or Hello Buzz etc but Yesterday he was like Buzzzz !n then I said hello, and he was like I meant to say zzzz I was like sure lol. He keeps calling me that. We talked and well I want him back. He has also message me when he was all drunk late at night, but I didn't read it till the next day, and if I don't reply he will message again saying hi or hey. It usually is now a 1 to 2 day gap, because I don't message him, he does. We message a lot and I'm always the one to let him go. Yesterday he asked for advice about he going to see a girl, I told him what he should do in his best interest. I want him back, I just don't know how. He also got mad when feelings were being brought up, not directly, but he got bothered by it. He shares what goes on his life on his own, and well yeah id appreciate the advice.
What does it mean when your ex starts calling you your old nickname he gave you?
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