Is my boyfriend getting bored with me?

My boyfriend and I have been dating for 6 months and I love him and he has told me he loves me. In the beginning and even the middle of our relationship, he sent me random cute messages and always complimented me. He would show me off in front of his friends and always put me first. I’m not the high maintenance type of girl; I just thought he was doing all this because he was happy he was dating me and stuff. But lately things have changed. He rarely compliments me, just the occasional “you’re cute.” I have said I love you to him and he changes the topic without saying it back. Also, I’ve tried like flirting and keeping our relationship fun but he just tells me I’m weird or that he’s tired. I’ve asked him if everything was alright and he always replies with “I’m fine.” When we are together, he sits there on his phone texting other girls and playing games. I don’t know what’s wrong… Is he bored with me? What should I do?