Why is one of my guy friends ignoring me?

Hi, so In year 8 I used to be really close to 1 of my guy friends when he was recently the new kid. We were still strong friends in the beginning of year 9 also. We used to talk to eachother every day 5 days a week. I don't know what it is but he has been kind of ignoring me. It's not full on ignoring me but i would be lucky to get about 1 sentence a week of conversation. He used to call me his "best bud" but now he is really close to this other girl Carys. They are really close now but like Carys is flirting with him a LOT but it looks like he dosent even wanna be her boyfriend. She even hugs him and ruffles his hair, but he looks really uncomfortable when she does it. I don't know if it's coz maybe she prettier than me, but in my opinion she is a cake face ( soz for the critisism) and is always the centre of attention. I used to fancy him but I am totally over him, but he dosen't know that I did and I swear I didn't tell one of his mates. He doesn't turn around to look at me or nothing. He used to love all my jokes and we used to play fight with eachother but now it's all stopped. The strange thing is, is that when Carys went on holiday for a month he was starting to talk to me again. I am so confused!! Plz help me, thanks for reading my question. Xx