Snapped at my buddy at the gym today....?

For months he's been getting on me about how i'm"not working"I finally snapped at him ,and said why the hell would you make such umptions when you don't even know anything about my private life?He Said he was just joking and he had to apoligize to me,after i pestered him about it.I asked him if he heard about it frosomebody about 20 times and he said no that it was his own conclusion he came to.In a joking manner.He said to lighten up and i take things too seriously.It's frustrating how hard i work at things,keeping in shape and other aspects,and other things that are hard work that i devote my time to,and he him knowing that,would have to make a comment like that.We kinda smoothed things over,because he didn't want me to blow up,,but it just pisses me off that i come to a place to work out,and he (being a buddy)disrupts my rhythm,he said he meant nothing malicious by it.He's also a musician like i am,so we definitely have that in common.however.he's in his late 50's and i'm 23.I'