Why is my best friend mad at me?

Ok, so today my friend just decided to randomly get mad at me. We are both 15 and I have a gf and he doesnt, so he always tells me that he wants a gf. So, these past few days I have been talking to my gf a lot on the phone because we like to talk, my friend was over my house when she called one time. I talked to her for like 5 minutes on the phone, after that, my friend went on and on about how much he wants a girlfriend. Then, another day when we were on xbox live, my gf called again, so i took out my mic to talk to her and then put my mic in after we were finished. My friend again says that he wishes he had a girlfriend, and I tried to be positive and say that he will find the perfect girl for him and stuff like that, and i meant it. So, today we were supposed to hang out and he ditched me. I asked him why he ditched me, and then he said he forgot, and then he cursed me off. He also said things like stop rubbing my gf in his face and called me a jew. So, I asked him what was wrong and he continued to curse me off. That pissed me off, so I started to fight back with him and told him to **** off. He started acting like this randomly and it got me to the point where I wanted to have a real fight with him. Whats his problem, is he jealous of me or something, because I did absolutely nothing to him. For the record I am not jewish and he knows that because we had christmas together once. Please answer in detail. No trolls! Seriously, a real best friend would be happy for me that I have a gf. Please give me some good answers soon, cause I'm one more step away from meeting him somewhere and fighting it out with him!