Bf all of a sudden cold

So my bf has all of a sudden been withholding love and all of a sudden being odd. One weekend he is in love with me the next he’s acting very strange. He hardly wants to take me out and would rather bring food home and doesn’t do anything nice for me. It’s hard to understand what is happening because he’s usually so nice and sweet and it’s left me all kinds of confused. He won’t even put his arm around me on the couch. I tried talking to him about it but he just kept shaking his head yes but I got no response in why or how to even fix this. Every time I leave the room he is on his phone but does put it down when I come back but that’s just odd also. It’s like he’s completely disconnected from relationship but when I ask him if he wants some space he won’t take it. I encourage he go play ball at gym with his friend and stay back at his house to try and give him space and he says “no”. I’m so completely confused and lost.