Not putting in effort


So my boyfriend and I have been dating for 1 month now and I feel like he’s not making an effort I’ll try to talk to him and he won’t carry on the conversation he will just reply with yeah, cool, nice and it kind of makes me feel like he doesn’t care I talked to him about it and he said he won’t reply like that anymore but I’m still a little worried what should I do🤷‍♀️.